will not be in your 2000 - it is a type of epoxy paint found in 50's & 60's trailers. It has a splatter-paint appearance to it.
is what you described as Zolatone in your opening post - it is basically vinyl wallcovering usually with a texture & printed pattern firmly bonded to the aluminum skin. It's usually found in wet areas like the Kitchen & Bath.
is a soft fuzzy fabric. It can be smooth like velvet or have a texture similar to a soft loopy carpet. This is usually found in the living & bedroom areas.
Padded Cell Ceiling
is as you described but it's basically padded vinyl cushion-like (knit fabric or foam-backed?) material on the ceiling. It's a sort of vinyl faced headliner - much like what is found in some cars.
From your pictures:
#1 & #2 look like Vinyl Clad Aluminum
#3 & #4 look like Mouse Fur
and #5 looks like vinyl padded ceiling
Q-1: I would use some something like Simple Green or TSP to clean the vinyl-clad walls. The Lacquer thinner is way too strong - it is removing the printed pattern - thus leaving the solid white vinyl.
Q-2: I've never owned a trailer with this, not sure of any cleaning recommendations. Someone that has will surely reply, but my inclination would be to try cleaning it with something like a mild dilution of OxyClean.
Q-3: Again, not dealt with this first-hand, but I think what happens is either the foam backing disintegrates and separates from the vinyl face or the vinyl just comes un-glued from the aluminum skin. Some have had success re-gluing it, others have stripped it completely off.