This looks like a fun project. Gaming Shaft with Predators is bound to make for a few giggles.
Whata rules are you planning to use?
Tying the two quite different looking factions together thematically might be fun.
Painting the three dot laser sight over Shafts heart could be a fun way to tie them together. Putting some 70's themed bits (like, I dont know, a "Saturday Night Fever" 7" or something) on the Predator bases could be amusing too.