Hokay. I'm lazy and haven't 'shopped any pb faces onto the stock pics yet, might do that later. But for now:
Cannonball: Confederate general, though without that hideous Yosemite Sam mustache Chamber: Phantom! (this will work until I find a better costume, but you get the general idea) Cleric: Harley Quinn, for her puddin' Pyro: Fireman, because we all love a little irony.