I build a hanging shelf for my latest projector set up, so I could sit the projector on the shelf, verse hang it upside down....I have an anamorphic lens in front of it too, mounted directly to the same shelf. It's mounted directly to the floor joists of the second floor above. When I originally hung the projector, I too was concerned about the upper floor and/or bass vibrations. Neither ended up being an issue. I have a Stewart screen (2.40 scope screen) mounted directly to the wall. No issues with that either.
