A customer just sent me this photo, my first thought is that the head is not cake. What could I use for the head?
Either RKT or a styrofoam ball. I'd use a thick foam cakeboard and push the head down on a sharpened dowel that goes down into the cakeboard and most of the way up through the head .... just to keep the whole thing together and stable. In fact, I'd probably do the entire figure this way - as a cake topper - and then position it on a square or round layer cake.
If you look closely at the head, it looks like it is made using the ball pan. There's a seam at the back of the head.
I made a Mickey cake similar to this style of cake and I used RKT for the head. The body and present were cake. And yes, use a dowel all the way thru!!