Well, let me see how I understand the group dynamic based on tasks we might face:

Infiltration is fairly well covered. Soot can sneak in, Dive Bomb can create a diversion, Crown Cork could probably grease his way in with his influence.

Dive Bomb covers medicine, and he and City Slicker can probably figure out navigation.

Grease Spot can probably figure her way around a trap, unlock doors, or figure out how to trap enemies.

The only real issue that I can see is direct combat. I'd probably be limited to chucking a stick of dynamite and then trying to snipe stuff with lightning bolts.