I think I peed my pants a little.
UPDATE: Spanish site MeriStation has an interview with Iizuka. It’s subtitled in Spanish, but intercut with the interview is gameplay footage! Tons of awesome stuff to see here:
Iizuka does note that Tails, Knuckles, Shadow and others appear in the game. He does not say if they are non-playable characters or not, but based on the game description I’m going to assume NPC.Ad: