Though Meghan McCarthy has already put the kabosh on a Sunset Shimmer storyline in the show, I suspect that she may still appear. Why?

* The similarity of her name to another character's

* "Years ago, she was also a student of Princess Celestia"

* She's a unicorn

* Her figurine is part of a series of masked ponies — along with Applejack, Fluttershy, Pinkie Pie, Rainbow Dash, and Rarity

Gosh, isn't there somepony's name missing there in that last bullet point? Hmmm... Could Sunset Shimmer be a disguise for Princess Twilight Sparkle? It's a pretty common trope that Celestia and Luna periodically mingle as regular ponies, after all, so why not Twilight?