The hybrids are all the Jes Goodwin sculpts, who were clearly innspired by both the Navigator Guild and Harkonnen costumes of David Lynch's Dune film.
The Brood Brothers, infected human soldiers, with colours loosely based on the Nostromo crew's spacesuits from Alien.
The miniatures are Bob Naismith's Cobalt-1 security troops. Rogue Trader Redux Approved.
Much of the designs for Dune were done by the same people who did Alien, so it all makes sense.
This group among whom Moebius and H.R. Giger, initially met thanks to Alejandro Jodorowski when they worked on his never released Dune film which could have been he most insane lysergic science fiction film ever made.
(As a complete coincedence and to me by surprise, GW recently released new genestealer hybrids, something I didn't believe and had dismissed as wishful thinking by fanboys until a week before release.)