Hey, thanks for playing and ofr the in-depth feedback!
You can actually move most of the equipped items between characters. They are shown on top of the details on the right side as small symbols and can be dragged to other characters / to the sell button. (Greyed out items can not be moved though, such as mad brain).
Uh we thought about minions that could would be stuck in walls, but it rarely happened I think (didn't happen to me at least). Sorry for that.