Worm Jeff tried to forcibly convert Hoody and Masky into Proxy/Drone hybrids in "The Worm In Paradise" saga (which I haven't finished yet) but was stopped just in the nick of time. So yes, they CAN be infected.
Well, I never thought of that. Jeff Crawlers, which are the "tanks" of his forces, are creatures that are formed from huge masses the corpses of infectees melded together and reanimated via magic. So yeah, I guess technically he can.