This is rather petty, but I'm a stickler for aesthetics in games. always love them, especially when they add more immersion.
My suggestion is to either add a rigging bone on the right buttocks or to use the existing rigging bone for the right hip flap.
This option would hide the helmet of the character, but also place the equipped helmet model on the side of the character. Attaching it at the rear base of the helmet I think would help resolve most clipping issues. Either remove the hip flap as well, or not (depending on what bone is used)
What're your guys thoughts on things like this?