Use Eduardo in a Juggernaut style rushing attack. Wilt throws a basketball projectile. Herriman comes down as an overhead and bounces back to where he came from. Mac fishes something out of his backpack such as a health recovery item or some kind of power-up. And you've already incorporated Bloo as the block which is a good idea.
I think the obvious way go for Madam Foster would be strikers. Various Imaginary Friends. Wilt, Eduardo, Bloo. Maybe even Mr. Harriman.(sp?) You could probably get plenty of voice samples of her calling their names and what not. Also, as far as CC on the sprites, you need to do more with her hair. Have it bob as she walks and make it bend when she's laying dead on the ground.