I'd expect Utsuho and Suwako to stay, too, provided there's a Shinto/Moriya side to the faith battle. And I can't honestly see them skipping on this. Maybe team up with Reimu to uphold the Good Old Ways against the newcomers or something. The SDM crew looks likely to be out, though, and unless they pull a Keine/Mokou/Kaguya/Wriggle (oh please) out of their hat, i can't see IN having much presence either.

Gameplay wise, I hope spell cards stay in some way, that weather is done with (or at least that they remove Typhoon ) and that whatever mechanic is hinted at by those yes/no/undecided circles around the character portraits is fun but as unintrusive in normal gameplay as possible.