They said the first few episodes on the list were confirmed, and sure enough, we got Stranger Than Fan Fiction and The Cart Before the Ponies.
Which means the next episode after that will be 28 Pranks Later, and the one after that... The Times Are A Changeling.
So the big question is... which changeling will be involved?
If a common changeling, will he give mention as to what happened to Chrysalis and the other changelings? Will he confirm her to either be dead or living in exile?
If it is Chrysalis, being a one-shot episode it is not likely to be as epic as A Canterlot Wedding nor involve Rainbow Power, Crystal Heart, etc. Like when Discord returned. It ended with his redemption. The best I can hope for if it is Chrysalis is redemption, because being sent to Tartarus one way or the other is not likely to be in a one-shot episode, there'd have to be a huge battle and then them using Rainbow Power or Crystal Heart on her, and that kind of thing doesn't happen in one-shot episodes.
Again, if it is Chrysalis... well, I've already said this before so I don't need to say it again. Then again, if worst comes to worst I could just say it's a common changeling disguised as her to take her place, which of course will be huge headcanon.
Or, will they show Chrysalis at the end hinting at a two-parter involving her?