or, it would give the player controlling henry a choice between 4 that pop up like a choice screen in henry stickmin. the choices could be..
1. the airship which comes in from the background and rams all enemies against the screen
2. wombo combo from CtM which is just like that option, and ellie helps out
3.the teleporter you use the teleporter, which teleports all players to a variety of zones, before leaving them in the bank vault from BtB, where the cops attack your enemies
4. Charles, like you said.
one of his attacks could be hitting someone with the diamond
another could be him firing the rocket launcher, and just like in Etp, it goes around a pipe, and could hit someone behind henry
he would have regular punching and kicking attacks, but also he could throw random items that he can select from the series at the enemy players.
finally, I had the idea of using the taser grenade from FtC
let me know your thoughts on my ideas for his move set.