I see The Wonderful 101 more being Assist Trophies, and a random one of the main 6 will appear and call their power
Wonder Red: Unite Punch - a fist ploughs through the stage
Wonder Blue: Unite Sword - a sword swipes through
Wonder Pink: Unite Whip - self explanatory, whip on the stage
Wonder Green: Unite Gun - fires members of TW101 at people
Wonder Yellow: Unite Hammer - Hits the stage, stunning anyone on it and damaging anyone there
Wonder White: Unite Claw - Just slashes through the stage
Wonder Black: Unite Bomb - Slows everything down like Chaos Control
Would work rather well
Disclaimer: The above is speculation