Yes, the self-adhesive ones definitely have to go on a clean surface.  

If they're unpainted, use Loxon Block Surfacer as a primer, with 2 coats of A-100. 

J Scott, Example: My last bathroom remodel ended up after starting the project had floor rot that you could not see from the surface and a water leak in the wall.

I can start asking a million questions here, but I'm probably not even scratching the surface of my potential headache.

Flooring is the largest surface in the house, and it has to wear well.

Its also a lighter gauge material & on the install they did crack one piece so I would assume it's prone to stress cracking.Also be wary of the lighter gauge granite from China it is very prone to cracking & will surface scratch easily.We have Granite throughout our kitchen & house (14 years now) & it takes an amazing amount of abuse.

but I would say your chances are great, and that seems (on the surface) to be a pretty great deal.

underground, first floor or surface parking?

Clean the mold around the tub, re-surface the tub if it needs it, caulk the tub, get rid of the hand-held sprayer that will spray all over the place.EDIT:I might be inclined to leave the floor and vanity alone too ...

Silicone should be used only between two unpainted surfaces.