The body I made from a mannequin that originally was standing, but I sawed it apart and put him back together again but now sitting down. I used fibreglass with polyester resin, tape, some steel wire and a LOT of patience. It was not fun! Fibreglass itches, smells terrible and it a drag to work with in this kind of scale. Don't do it! I won't do it again.
The hands were also made in wax the same way as the head.