In what way is that a cello? There are no strings, hes holding the bow in the wrong hand
He has a bow in each hand. I think the metal plates on the sides are the component that gets bowed, kinda like a musical saw
I don’t think it is, but at the same time I’m also not sure what else I would call it. I suppose if I’ve got the structure of it right then it is quite analogous to a nail violin