Sorry for the late reply.

So if plants generate what is converted to magic, do they get their pre-magic from their food (seems unlikely as the most powerful magic users don’t seem to eat more, at least in portion to their power) or their environment? How is it that the EG girls have magic despite not/before having the external sources in their world.

How is it that the EG girls have magic despite not/before having the external sources in their world.

that doesn’t seem to explain how the stolen magic is a perpetual source as opposed to just the finite amount stolen at the time that should be quickly expent. If this body of magic is not the source of their magic then it seems like the “rune” in it. How does that oft observed “body of magic” fit into your theory?

Changeling shapeshifting only seems to copy the physical forms attributes

If they could just copy the magic they’d all just copy Twilight or Celestia and curb-stomp everyone in a fight, that they don’t use that power even when copying them means there must be some reason they can’t do that.

But given the extra effort Twilight had to use to use shapeshifter magic maybe unicorn magic is beyond changelings without such extensive preparation it was never worth using in the in-show time they should have if they could.

And since magic needs emotions, that changeling directly metabolize it and can’t generate their own hence needing to subsist off others, that’s evidence against their being able to use magic like unicorn (and why Chrysalis, the most powerful/skilled of them, could normally only use basic spells).

1. So if plants generate what is converted to magic, do they get their pre-magic from their food (seems unlikely as the most powerful magic users don’t seem to eat more, at least in portion to their power) or their environment? How is it that the EG girls have magic despite not/before having the external sources in their world.

3. Changeling shapeshifting only seems to copy the physical forms attributes, the only magic we’ve seen copied, pegasi flight, is something they already have as opposed to needing to copy. If they could just copy the magic they’d all just copy Twilight or Celestia and curb-stomp everyone in a fight, that they don’t use that power even when copying them means there must be some reason they can’t do that. (If they were that OP they’ve have conquered Equestria long ago and not need hundred to best the Mane Six as shown.) But given the extra effort Twilight had to use to use shapeshifter magic maybe unicorn magic is beyond changelings without such extensive preparation it was never worth using in the in-show time they should have if they could. And since magic needs emotions, that changeling directly metabolize it and can’t generate their own hence needing to subsist off others, that’s evidence against their being able to use magic like unicorn (and why Chrysalis, the most powerful/skilled of them, could normally only use basic spells).

1. Since the constant draining of magic appears to drain minerals from the soil (see Chrysalis’s throne and the dead-zone around the Hive), the gas is probably synthesized by plants - particularly those which do not exist on our world. The magical energy itself is some property of the gas’s molecular structure which makes it react to emotions in this way, I would wager (why it reacts, I have no idea - if that question was answerable, we could literally synthesize it IRL, so maybe that’s something that is impossible to answer / has no realistic answer - it’s naturally occurring in Equestria, which is all we know) - As for why a square means 3-dimensional movement - it could just be a naturally occurring result of the magic trying to make ‘sense’ of what it contacts and trying to increase order by making reality mimic the command?
2. That would make sense, and would provide a direct conversion of emotional/magical energy to kinetic force - which would be necessary for half of what we see. I like it.
3. Admittedly, no non-unicorns have actively teleported - it’s possible is IS complex enough that other species have difficulty mimicking it. However, changelings do seem to match the physical characteristics of anything they transform into (Chrysalis casually swimming through a frozen lake as a cragadile, for instance) - I wouldn’t say that it’s too much of a stretch to say that they can mimic unicorn capabilities too. Hell, depending on how finely they can control their transformations, they could have a separate organ for transformation magic, allowing the newly transformed horn to be fully functional.

1. Where does the base magic that runes program come from? Is it generated by the user or something else? Is it naturally occurring in Equestria?
2. If most of the work of the magic gas was due to it serving as a medium for storing/moving magical forces (shields/blast store energy that’s released as kinetic on impact hence simulating mass, whatever other energies cause their other effects) as opposed to the gas doing the work, that would reduce the amount of matter needed to from magic to something I’d consider plausible given user mass is never visibly depleted even from the highest volume magic/the plasma normally not being intense enough to cause damage.
3. About teleportation. Was there any non-unicorn telekinesis users (save elderichly powerful ones like Discord and maybe Grogar) shown to use teleportation without external artifacts/boosts? If not maybe it’s like how other flying races lack pegasus weather manipulation, it a level beyond what even similar races are capable of. Maybe changelings swap out that level of magic specialization for their shapeshifting powers (Chrysalis’s animation spell being an extension of that) which there’s no prescient for even the most capable unicorns or even alicorns copying (closes being a comic where Celestia uses an artifact for such). And teleportation runes can’t be assumed to be easy if it takes the most capable (Starlight) and knowledgeable (Sunburst) mages of their age together to do, and still be prone to catastrophic failure (if the fallibility was imagined you could also argue their ease of creation was). Such potential failure would explain why teleportation runes/artifacts are nearly nonexistent, as any with the ability/know-how for such would be safer using their own teleportation and one such disaster (combined Hindenburg with black holes/tele-fraging) to dissuade any widespread developments/use of such.

1. To be fair, a few other characters have shown themselves to be capable of short-range teleportation. These were all advanced mages (Twilight, Starlight, Cozy if you count the portal-aspect of her draining spell) - but multiple ponies have used it. It could be a close-guarded state secret, but as much as I doubt that in and of itself, i’d also state that Chrysalis was the ruler of a kingdom in her own right, which could have similarly discovered that spell. It can’t be that hard, even the name of one of the spells ‘imaginary’ Starlight was telling to sunburst in Celestial Advice basically gives away what you may need to do - Spacium Flexibus. Folding space.
2. It’s very possible that a blast of magic being sent out can be programmed to behave almost like a solid, which would look like a force field. As far as the mass it’s carrying, it’s possible that the molecule itself is EXTREMELY heavy, so magic is very dense. It’s possible that the volume held in Twilight in the S4 finale was actively condensed simply by its nature as magic ‘liking’ to condense (the orb made by Celly, Luna and Cadance was many times the size of her body after all) - and when she fired out a beam of it, the density was reduced substantially to achieve the massive volumes we saw.
3. The range decreased as we can see from S9E25. Since the shards were fired out from the explosion, it’s possible that there were simply none in range to inhibit their magic after Chrysalis’ defeat.
4. Indeed. I think that processing is where the runes come into play - the properties are changed to some extent on contact.

1. I accept that argument for Chrysalis being theoretically capable of teleportation runes, but that she nor anyone besides Neighsay used them means there must be some practical reason for their not using them. (Maybe such runic knowledge is rare/guarded enough Chrysalis never had a chance to study it. Maybe it still needs an external physical catalyst as a power source like said artifact that’s probative to come by.)
2. Magic blasts can impart such force the same way magnets can, force fields. If it were gas how can it be compresssed enough to impart force (if compressed by something that might support my theory that the gas effects are just part/byproduct of the medium of magic) or Twi physically store the volumes we’ve seen unleashed in the S4 finale in her person?
3. The throne retaining it’s functions once shattered is incorrect as it did lose it until the shards had it restored by external spell. How does that effect assumptions about it?
4. Tempest’s electric effects could be ionizing the air due to its lack of control as opposed to being ionized itself. And if it is ionized gas than it mean proper magic is converted/processed into something more complex than that.

1. Possible - but considering that Chrysalis would need one with considerably shorter range, and she’s shown to be capable of some pretty complex magic in the past. Going by the details of my rune theory, making intelligent life is going to be VERY hard compared to simple teleportation. Though I could be wrong. It’s hard to get concrete information one way or another on this topic.
2. True. Perhaps magic, to some degree, recognizes intent and specifics? In much the same way that Starlight’s anger at Trixie carried over to other ponies, who - overwhelmed - believed they possessed Starlight’s precise memories that she was angry at.

1. Rather than hollow/chromatophores, they contain the equivalent of organic liquid crystal displays. They’re higher resolution better meeting the clean geometries/text runes require and more susceptible to the kind of things we know can disrupt spell casing (other spells, anti-magic fields).
2. The Elements runes are in the form of their entire atomic composition, hence their being the most powerful things in the setting (as much runes as physically possible) an irreplaceability (too complex for any other medium).

1. Neighsay’s artifact is the only such thing we’ve ever seen. This suggests they’re exceedingly rare/hard to make hence why it wasn’t feasible for Chrysalis to track one down on short notice/we don’t see them used more often.
2. Even if babies have less control of their output that wouldn’t explain how foal are unable to generate similar willful outputs with the precise applications we’ve seen of babies. It’s equivalent to saying human infants are cable of better athletic feats than older children because they don’t have what hold older ones back.
3. The smooze bubble thing could be it explaining in the presence of a force field (telekinesis, blasts, and shields are such) as opposed to gas pressure. The force field properties of magic would give it the surface tension to have the appearance of gas (like Starlight’s anger) while not dissipating like a gas or plasma. And local life might be adapted to it but why are humans who are not unarmed much less benefit?
4. If magic was manipulated via magnetism why can’t they directly manipulate others cast magic (taking over ones telekinesis field as opposed to creating an opposing one, turning off opponents shields the same way their user would)? Even what draining/anti-magic methods we seen don’t work that way? This suggest whatever force manipulates magic it’s more precise/unique to the user than magnetism.

1. The thing is, we HAVE seen some form of teleportation artifact used quite casually by one character - Chancellor Neighsay. These objects obviously exist, and it probably wouldn’t be outside of Chrysalis’s capabilities to acquire one and then portal her way past some of the wind - unless there were other defenses in place to stop her…
2. The more that I think about it, the more that I think a leaky ‘magic storage’ is the best explanation for babies’ power surges. Babies are highly emotional to begin with, and if they cannot control how magic leaks into their horns, this highly charged magic will pour into the horn and generate random runes (in similar ways to how random objects in Equestria Girls get enchanted - without orders, magic will draw runes on random objects (even if those runes aren’t visible due to size or w/e) to give itself orders.
3. Unicorn horns are hollow, the interior surface (likely ridged or something to maximize surface area) is where the pigment is placed. As far as earth ponies and pegasi, some similar mechanism is probably in place in their bones and muscles - albeit, those runes could potentially be ‘always on’, and earth ponies could just have a finer control of the strength of their muscle contractions than humans would.
4. The elements are irreplaceable, since they carry a lot of raw magic from the pillars - which itself may be charged by the legends of the pillars, in much the same way that Flurry Heart was surrounded by love according to Thorax. Upon breaking, the magic of the elements chose the closest appropriate host to cling to - the element bearers (see https://derpibooru.org/images/2006702?q=uploader_id%3A405212 ). The young six may have been intentionally given some power by the tree, possibly some rubbed off on them due to their proximity to her ‘rebirth’ - or, my personal favorite, they were channeling the combined emotions of the entire army.
5. There are a few scenes which made me like the ‘magic is gas’ theory. You have the ‘anger magic’, and also the reaction of Celestia’s magic to her horn being coated with the smooze - both of those indicate that magic is gaseous, to me. As far as ionic gas being harmful, it’s possible that life in Equestria has evolved to be resistant to it - in much the same way that life on earth resists oxygen. Alternatively, the molecule is so massive that it just cannot get to the DNA without reacting with stuff first - so human contact with massive quantities of magic would be more likely to cause chemical burns / some level of crystallization than mutation (provided that it would react - and not, say, draw runes over your body uncontrollably while putting you into a crazed hyper-emotional state and giving you immense power if you can control the runes).
6. As far as how it’s manipulated not seeming to resemble methods used to manipulate ionic gas - for all we know, the tip of a unicorn’s horn becomes highly magnetic when they try to cast magic.

1. Chrysalis never teleported then because such long ranged teleportation requires power levels she’s only displayed after draining enough love to best Celestia or empowered by Grogar’s Bell. Her baseline beyond default changeling abilities is telekinesis and magic blasts which are below the level of magic fitness teleportation requires (her mind manipulation involves her emotion powers such it doesn’t translate to the skill equivalent for of unicorn mind magic). Before the Bell I don’t think she was portrayed as capable of teleportation at all. And if teleportation runes existed/were more practical than regular teleportation why haven’t they been seen/used for personal travel more often as opposed to trains/hot air balloons/such?
2. If that’s why babies magic is stronger why do adults not have similar amounts of external magic flowing into them? How do babies have an easier time covering their uncontrolled magic into coherent spells/powers than foals? Why do foals have learn as opposed to unlearn to use magic then?
3. If unicorn horns use pigment cell to create runes why have they never been shown to change/shift in color? How do earth/pegasi (who can turn of their flight/strength as needed) do likewise?
4. Internal runes may semi-explain the Elements (Why are they so irreplaceable if their power is just text? How where the Mane/Young Six able to use their power without the physical Elements by the series end?), but what about Discord who never seemed to use such (save when hiding his identity as Grogar)?
5. How does magic being a physical gas better fit their observed properties than if it were a some form of massless energy field with properties that made if self-coherent and manipulatable? (How it’s manipulated doesn’t resemble what would be use to manipulate ionic gas which would harm plants/life as opposed to harm them by extracting? If evolved to take advantage of it could be for reason other than being physical matter. How would ionic gas empower as opposed to be harmful EG humans who don’t have such adaptation/runes?

1. That is a good point. This could be a difference between the EqG and core MLP universes, as I don’t believe that we have seen intangible magic outside of EqG. As far as hazmat suits etc go, it’s entirely possible that pony-designed suits have some form of reading mechanism which allow them to mimic the spells carved on the inside of a unicorn’s horn (place an eye and square rune in the horn region, with text demanding the appropriate effect if my theories hold).

2. If Discord’s magic relies on maximizing the uncertainty principle, surely that would break upon attempted use by any other being? Their horns etc wouldn’t function in the same way as his, and would try to ‘analyze’ the magic deeply, merely reducing its power instead of making it outright rebel against the user.

3. This does not disagree with my assertions, at least :)
4. I think of the runes in a unicorn horn as akin to an iguana’s skin changing color. You have a spiral surface (or something akin to one) which generates IMMENSE surface area, and then neuronal input makes the ‘horn cells’ generate pigment on this gigantic canvas, in the exact pattern which a unicorn desires. This is highly complex, but feasible biologically. The runes change as they get better, since they are consciously altering them themselves. Magic draining works by sucking out the ‘chemical’ magic which reads and reacts to runes, and containing it elsewhere - no chemical magic to read it, and the runes are just pretty pictures which even we could draw.
5. The elements seem to be stores of raw energy, without too much complexity - but it isn’t too hard to imagine that maybe some runes are on the interior side of the elements. Almost like a ‘geode’ (hi EqG)
6. As far as it being beyond suspension of disbelief - we have only ever seen magic from two sources. Biological, and rune-based. It is unlikely that the same force would respond to two vastly different systems, and biology is capable of generating large runes in a small space. Occam’s razor.
7. To clarify my position. Magic itself is a chemical. That magic gets charged by close proximity to a being experiencing emotions, and then comes into physical contact (or close proximity) with a rune. The magic detects this rune, reads the overall structure, and uses the ‘charge’ it has gathered to fulfill the demand made of it, in an effort to reduce local entropy / reduce entropy in one region and generate heat elsewhere as a result / maximize some semblance of ‘order’.

1. True about magic. But all the loose magic we’ve seen in both worlds never had the instantly move at opposed to travel from point A to B effect we’ve seen in teleportation, and only rare/specific spellcating allowed intangibility. If it were as gas, it would be effected/dissipated by wind, rain, or other environmental factors such it would be apparent if the case (any evidence of such?). And it requiring those generating it to obey conservation of mass/energy despite magic frequently breaking it seems so arbitrary it would make more sense if it were pure fanatical. Thus I still think it makes more sense magic is a massless energy even if it has properties similar to matter.

2. Good point about Discord, he’s chaotic but not anti-entropic (unless there’s some cost outside the observed system we’re missing). This leads me to believe works like quantum mechanics, which allow normally brief breaches of entropy that magic allows to control/scale up to macro scale. Uncertainty principle applies to magic in the more energy you put precise measurements (a powerful/complex spell, analyzing magic), the more you change what was measured (making such volatile and fleeting). This is why Discord’s magic is so powerful (the price is it being so hard to do something specific only chaotic beings can control it with “precision”), why babies have powerful magic spurts (powerful because they lack continuous control which weakens it so such power must be re-learned), and emotions are such a powerful source of magic (emotions replace the conscious thought that would reduce the pool of usable magic), Sunset and Sci-Twi’s attempt to analysis magic with scientific precision literally and metaphorically blew up. Orderly magics like Star Swirls banishing spells and magic items require equivalent exchange (sacrifices, the effort to make said item).
3. The forces holding free magic together against (but not necessarily in violation of) entropy are not ionic for the reasons discussed, but I theories something that would normally be abstract, identity. Magic make self a physical force powerful enough to keep stolen magic separate as opposed to irreversibly mixing with other magic/dissipating and draws it back to its owner once freed. It is the force of the purpose of complex spells that hold them together as long as they do. It’s magics ability to conflate abstract with physical that lets it violate entropy.
4. Runes are shown to be limited one specific spell each, so do they somehow get new runes when they learn new spells/abilities? Do the runes change as they get better at using said magic? How does magic draining/anti-magic work as most don’t work in a way that could physically alter runes? If runes are added/altered magically doesn’t that mix up the stated cause and effect?

• “Magic is a gas” is at odds with how we’ve seen it reflected by mirrors, pass through solids, and has never been shown to deplete physical matter from its users (if it’s rearranging matter it still means there’s a non-matter source). It seems more likely magic is more like photons (Sci-Twi states it’s electromagnetic) as opposed to physical substance, the light and electrical things you pointed out being due to their interaction with atmosphere as opposed to the magic itself. If phonic gems optical properties would be good at capturing/interacting with magic hence their connection (dragons I assumed eat gems more because they’re (partially?) silicon-based thus their heat-proofness/durability, as Spike suffered no distinct effect from Tirek draining him). It has some properties that let it be externally attracted and interact with matter such it’s absence drains life from plants, but it’s likely different than electrical/magnetic charge as only some of what’s used to drain magic have similarities to lightning rods/ionizers/magnets. As for gems abundance it could be magic intreating with earth (but that would suggest they’re more associated with earth ponies than we’ve seen), or maybe Equestria’s just luck to have geologic conditions more suitable to gem abundance than Earth (far less unlucky than what ever differences mean the sun/moon have to be manually moved).
• “Magic hates disorder” is contradicted by the very disorderly Discord being the most powerful singular entity in the series. That all the anti-magic/magic draining thing have effected Discord’s chaos magic means it’s sufficiently similar to orderly magic despite differences in use they must be fundamentally the same thing. That loose magic balls up as opposed to dissipates could be like raindrops in their internal forces are sufficient to hold them together.