I'm good with playing multiple characters
With Hans you can play him if you want? He could try to take over Anna? I haven't really planned Hans out that well or what results he would have - if he lost or hurt Elsa, Anna would punish him I would imagine unless he won against Anna?
With the ideas I think going with the frozen one and Annie finding out Misaka wetting the bed are the best two to do.
I'm pretty much okay with anything. I don't really have any taboos when it comes to roleplaying. Yourself? But to be less vague I do enjoy humiliation and corporal punishment in roleplays with a touch of comfort here and there.