Glad these are so well received--the praise means a lot from this group of artists!
The heads were individually sculpted from Apoxie sculpt. Initially the antennae were as well, however, they tended to be a bit fragile. I redid the antennae and mouthparts in a flex Sculpey product to allow for some flexibility, and they seem to be holding up much better.
I should add that I was inspired by I-Am-Boba-Fett's Clone Wars-styled Verpine Jedi, but wanted to blend with Vintage Collection figures. He has this posted in his thread. It's worth checking out.