I came in to mention Goblin’s Suspiria score, but I also liked Marco Beltrami’s score for Scream.
“Picnic At Hanging Rock”.
It reminded me of that M.C. Escher picture of grim dwarves climbing a staircase on the top edge of a tower, going endlessly up in all four directions. My impression at the time was that the music involved a slow chromatic scales that, like the stairs, seemed to always be ascending. It created a sense of unbearable tension.
The movie does move kinda slowly, but I never forgot that music.
Those are great questions, Scrivener, and I’m sorry to say that I don’t know the answers yet, but I’ll pass them along to Randy and see what he knows. Everything is in the way early stages and we have yet to see any footage.
Actually, James Horner did the score for Aliens and Elliot Goldenthal for Alien 3.
One of my all-time favorites that nobody’s mentioned yet is Philip Glass’s amazing score for Candyman (which itself is vastly underrated).
And of course, there’s Max Steiner’s seminal score for King Kong (perhaps the first truly great film score).
For a very different horror soundtrack, you should check out the music for cannibal horror film Ravenous. It was written by Damon Albarn (Blur) and Michael Nyman, and very disturbing in a claustrophobia-with-banjos sort of way.
Look at any of the horror by Harry Manfredini , most famous for Friday the 13th (ch…ch…ch…ah…ah…ah…) but his creepiest masterpiece are the soundtracks for House and House 2. They are mostly cello and string, and ooze suspense and tension 
Right you are. Goldsmith did only the first Alien of the sequence. Not much continuity in the music department, it seems.