Claus doesn't have bones, he just solidifies his body to simulate bones.

He can change his hair style anytime.

He can shapeshift into anyone, if he has enough energy that is.

(He'll still look the same, ir's merely just changing his body type.)

Claus can withstand a lot of weight...

Even if Echo falls or sits on Claus's face or pelvis, he'll be fine.

He can withstand the sheer force of her ass XD.

(Echo's ass cheeks clapping could probably make the world shake, lol.)