Concept 1: Body Dweller, Face Smasher and Cygon 
These are very odd (and disturbing). Did my parents know that I was drawing this stuff? The Body Dweller image was obviously burned into my mind after the brief look at my uncle's Giger ALIEN Film Design book which he bought at the cinema in 1979. I mean, pretend you've never seen that before. Now, imagine you are 11 years old and seeing a disgusting creature inserting itself in someone's mouth and laying eggs. Even worse, imagine that - having not seen the film yet - it looks as though the person in Giger's image is some sort of Nazi-style lab guinea pig - a poor unfortunate forcibly placed there, unconscious. It's a bit like that awful ALIEN Ressurection film isn't it? Maybe it's a good thing I didn't actually see the film until I was about 13 (?)
The Body Smasher is a curious one. I must have seen an image somewhere of Brett having his head crushed. Ah, such a lovely image - and what a sweet boy!
The Cygon? Sounds suspiciously like CYLON to me. I used to watch Battlestar Galactica in the absence of Star Wars out of sheer desperation. Guiltily enjoying it - but resenting what I perceived as its absolute brass neck for even existing in the same universe as Star Wars.
Is the Nostromo(s) in the Giger book? It must be. And the FLAGEN. (rolls eyes) I took ALIEN to be the usual Sci-fi fare with lasers and baddies shooting it out with one another. I'm thinking that Flagen (rolls eyes again) was a word I picked up during Northern Irish visits where people would be talking about drinking Flagons of cider and Nagons of whiskey.
Thankfully this stuff never made it to the screen!