For #1 maybe the sound from Ocarina of Time when you center the view with Z-target. There are actually 2 sounds, one of them is pretty short and sounds like a stone floor scraping.
Now that I think of it, that might work for both, if you make the first one (creaking/crumbling) a bit quieter and lower-pitched.
After 4,000 sounds I'm starting to forget what I've got available.