Well that was fast. *Update* · 10:38pm Jun 10th, 2014
So some spoilers from Amy Keating Roger's new book about Celestia and Luna are floating about, and it's not looking good for Though Ice and Shadow.
Journal of the Two Sisters spoilers ahead
Beyond having to change Crystal's name, a few things regarding the Empire's founding, and mentioning a scene about a dragon--I'm sure I'm still going to have to do some extensive rewrites if I want to keep the story somewhat canon.