The problem with adhesive on drywall is that the paper surface is not well attached to core of the drywall. Also, the rivets may not go through the drywall.
The surround should be completely waterproof, and it may be possible to install it on the frame or furring strips. You should probably look at one at HD or some place before you buy it on line.
There are shower conversions that use a flexible tube from the special tub diverter spout, with the head mounted on a bracket on the wall or on the surround. That would solve the problem of the not having the tub spout just below where you may want the shower head.