On the one hand, I definitely like the idea of a ‘real Equestria’ counterpart of Professor Flintheart being a not-so-healthy influence Starlight’s attitudes and/or magical powers, though moreso if he were like a mad hermit or some such outcast.
 
On the other hand, I wouldn’t want him to get too much credit either, because I am not a fan of removing too much direct responsibility for characters’ mistakes and sins. Surely Starlight would have to be open to the dark side to learn from it, no?
 
Not that you CAN’T have a ‘its cause they had a bad childhood’ explanation,  
it’s just such an overdone story excuse, and makes the character seem weak and easily manipulated.  
I prefer willfully-at-fault Starlight the same way I do Luna-as-Nightmare-Moon.

@Background Pony #A12A  

 
Neither are Mr. and Mrs. Paleo Starlight’s parents, they just make useful stand-ins.
 
Also this…
 

The snowfall frost part makes no sense. That is in a book that twilight reads, that isn’t her back story, its basically the ponfied version of A Christmas Story. So there was no ‘snape’ character that we know of.

Curiously enough, you and BobtheDalek arrived at similar conclusions:
 

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your current filter.

 
That’s enough to get a Headcanon: Accepted out of me.

@Background Pony #8EC1  

 
Well, now she has a support group that can actually help her and genuinely caring mentor who will guide her towards a better and more responsible use of her gift.

Interesting. I doubt they will go this way in canon, but it has merit.
 
The effect of this would be that no matter how hard she tries, she’ll always gravitate towards the misuse of magic, no matter how many friends she gets or how close and deep their friendship is.
 
You know, like opening an uncontrolled magical porthole in her friend’s home and getting both of them sucked in.