I suppose another thing to think about is that certain entities in Giger's paintings, I assume the Necronom series as well , were supposed to be people in exoskeletons, perhaps one might think almost as protective suits, maybe Scott was somehow playing with that level of thought.
In the Longer version of "Alien Evolution" documentary Giger said said "I wanted to make something that would be somehow human but that would also be robot-like, a kind of human that is protected from all kinds of external forces, be they weapons, radiation or whatever else. Instead of having their bones on the inside, they have them, partly at least, on the outside like an exo-skeleton. I mixed these together, this world of bones , mixed it with technical things, that's how these 'biomechanoids' came about from the interplay of the biological and the mechanical."
However in the shorter version, the man who does an English voice over during the Giger's section says ""I wanted to make something that would be somehow human but that would also be robot-like, that is to say a kind of human being that is protected by bone. And I mixed these together, this world of bones , I mixed it with technical things, that's how these 'biomechanoids' came about, that is from the biological and the mechanical interplay of the two."