Another tidbit of news we learn from the Game Informer article is that Dr. Eggman has already taken over the world –
There's no way this is a resolution to the ending of Sonic Chronicles
But this game NEEDS to be a resolution to the ending of Sonic Chronicles.
It's like 100% certain they're just going to have an opening cinematic like in Sonic Unleashed where they have Sonic show up to fight Eggman in some random adventure only for Eggman to unexpectedly win and keep the whole story self-contained, but it's still going to be my head canon that this game serves to wrap up Sonic Chronicles' cliff hanger.