I have finished working on the head piece. My head is a little bigger than the foam one, so it sits a little higher on the head than in the picture.
As you can see, I found a nice bright red wig! This should be very striking against the white clothing and pale greenish face. So far, this seems pretty promising. The construction was a little more challenging than I had thought, but I think I found my solution. After testing a few different adhesive methods, I found simple craft glue to be the best way of initially sticking the layers together. Once the glue dried, however, the pieces lifted apart at the edges, so I carefully stitched the edges down with white thread, using very small stitches. Once everything was nice and secure, I punched small holes along the top edge, and put small white paper brads in the holes.