In order to get this film done I have completely given up trying to make proper armatures opting instead for savage twists of wire crammed into the casts quickly enough so I can't protest my doing it. Ooo-rah. I use almaloy and steel of various weights. Then I wrap with sports tapes and yarn. I add bones made from split drinking straws and fix the finished armature inside the cast shells with masking tape.
Then it's a matter of finishing the sculpture by building up with foam and more masking tape until the character is ready to be finished with wings, hair, paint, shading, etc. Above lower right you can see the beginning of Yanu's wing installation.