look at netsuke's online, and then the kids can make clay balls the size of snowballs, and carve into it. These look great when done. My students did them out of plaster (we made plaster balls and then carved them). You can use simple tools for carving, not anything dangerous. Netsukes are small in the original form as they are beads used in kimono wearing, you are just blowing up the idea to have them carve animals on a round shape.
clay beads. Look at big chunky necklaces and pendants on Etsy.com, and then you can have them make clay beads/pendants and make jewelry
personally I think plaster guaze masks and hands are overdone (George Segal), but check out this video on how to combine papermache with the guaze.