Knuckle's Chaotix
Playable characters: Knuckles, and Mighty the Armadillo(possibilty that all other chaotix characters MIGHT become available in side missions)
Rivals(note subject to change): Metal Knuckles, Fang the sniper, and Rouge the bat
New allies: Mecha Knuckles(archie), Ray the flying Squirrel, Bomb and Heavy, Omega, possibly more
New Levels: Mushroom hill zone, Retro Deathtrap, NEO-Eggfleet, Newtrogenic high zone( its on Angel island of all places ;)), more are planned, but several ports, and several are under wraps
Silver Sonic conversion
replacements: Silver sonic, Silver Sonic 2, Tails Doll, Metal Tails, mecha Knuckles(or metal, both are the game versions, different than the archie one for KC), shiny Shadow android, and more
more may come along later but these are the basic things planned