Would it have been possible to etch the robot face into either the back or bottom of the rhino head like Tantrum?
i suppose so? not really sure what you intend to gain from asking. Noone here worked on it so any answer is purely hypothetical.
no, but it is nice that he does have a separate head, now isn't it? so what's there to complain about? if he didn't have a separate piece, you or some one else would be complaining "why didn't they make his head and beast head separate! how cheap!"