Capcom's released details about the game's alternate costumes — and they are amazing. Instead of changing each character's costume colours, Capcom has instead opted to dress the roster in clothes from other characters in the game.
For example, above you'll see a screenshot of Poison dressed as Lily and Zangief dressed as Kuma. Amazing. Other shots on the Capcom blog show Chun-Li kitted out in Panda's gear, and Cammy cosplaying King.