Yes. Tiled or vinyl. Be sure to caulk any gaps
Yes, with some alteration. The plastic can be carefully measured and cut with a utility knife to match the specific angle of your tub wall. Cut to match the vertical wall and leave the horizontal footing as it is.
My thinking is . Always have curtain inside, otherwise water could run out on floor, . If outside, why have a curtain at all?
I have used it for more than a month and have had no soap scum build up I wipe it when cleaning the shower.
Fill in gabs with the clear or white silicone adhesive tube stuff.
Only held on with clear silicone caulk so yes easy to remove or reuse.