Heh. Browsing the old comments on this image was fun. Looking back at old speculation with the benefit of hindsight is always interesting.
 
Come to think of it, though, it’s kind of odd that Silverstream was introduced this way on her own, without any of the other students for reference.

@Background Pony #FF37  
It’s a slide of presentation at panel. What did you expect, Arial and white background?

I love how she’s announced here like the big deal.

@Background Pony #B87C  
Silverstream is best stair lover.

She’s a character in Season 8 now…
 
And she loves S T A I R S

@Dec Browne How do I know what she actually IS?

You’d think that with a name like Silver Stream, she’d have chosen to stay a seapony, but she became a hippogriff.

I seriously dig her design.  
Her colours.

I’m not sure how it took me this long to notice – that’s Seaquestria’s columnar basalt formations in the background. Neat.

This better not be another hippogriff, man!

@Background Pony #54F2  
The movie’s cannon

@Background Pony #54F2 He meant canon. Must be autocorrect.

@MuttonBash - But the movie is not a cannon, though.

@Background Pony #8C89 Thanks for the advice. Although, I had ideas where Novo, a Queen, would tell Celestia, a princess, that the former and her kingdom should not fall under the latter’s jurisdiction since it looks like she has no control over those nations. That would infuriate her and start conflicts, resulting in two sides forming, Skystar joining Celestia’s as a princess, worsening a rift between the mother and daughter.

@Kaden Bayne Vanciel  

I’m pretty sure that was implicitly lifted after Storm King’s defeat. If you think she can’t visit as a pony without drowning, Twilight needed the Orb only for mass-transforming the army, temporarily transforming herself and her friends she can handle herself.  

I would say they would just treat it as two districts of one city, but Orb is quite inconvenient. It doesn’t give the power to transform, it just transforms, so it’s kinda useless in that regard.

@FrustrationInExcelsis Dunno if she’ll play any major roles in an episode, or if Chenoweth and Aduba are reprising their roles for Season 8. With the hippogriff kingdom restored, how does it seal Seaquestria’s fate, and the Mane 6’s blacklisting from it thanks to Twilight’s attempt to steal the orb? Who knows which hippogriffs are becoming that again or staying sea pony, or becoming 1/3 bird 1/3 fish 1/3 horse?

@Background Pony #262B
 
I’d think they do, yes.
 
@Kaden Bayne Vanciel
 
I think Silver Stream was confirmed as appearing in Season 8 at the Hascon panel this screenshot appeared at.

She might appear in Season 8. Dunno about Skystar or Novo appearing though.

@Dec Browne  
Do the chapter books count as side canon?

@FrustrationInExcelsis  
The only time side canon has been introduced in the show is when Blossomforth, who was first a toy pony, was introduced.

@Background Pony #8C89
 
I doubt that, for two reasons:
 
First, the show has not shown any real tendency to go out of its way to include side canon into its continuity. If anything, it has tended to contradict it instead (for instance, the Root of the Problem arc of the comics had intelligent, civilized deer as major characters, but every time deer have appeared in the show they’ve been animals; the Chaos Theory arc had Discord changing himself from chaotic to orderly and becoming a god of law rather than a god of chaos, but “Discordant Harmony”, which came out nearly a year later, said that that would be impossible – Discord would jut disappear if he stopped being chaotic, and as such wouldn’t have survived becoming “Accord”.)
 
Second, and more importantly: Silver Stream doesn’t really look anything like the Aquastrian seaponies. They were basically giant, colorful seahorses, rather than the movie’s hippocampi. She has legs and a tail fin, which the Aquastrian seaponies lacked, and she herself lacks the striped coloration of the Aquastrians.
 

@FrustrationInExcelsis  
Maybe she’s from Aquastria, not from Seaquestria. (I.e. not hippogriff)

SHE BETTER NOT BECOME A HIPPOGRIFF BY THE END!

Maybe she preferred the undersea life and opted to stay underwater.

@FrustrationInExcelsis  
They’re using a breath spell in the movie before any of the transformation stuff.