Durarock or Denshield for shower?
I have used denshield for non wet applications, but always use durock for wet jobs. The best insurance is to use a barrier behind the durock for any possible moisture problems. I still like the old standby of 30lb. felt. Green board in a truly wet application like a shower is a disaster waiting to happen. I would never install a shower floor on plywood.
It needs a waterproof pan with a morter bed for the tile, or one of the new cast resin pans designed to have tile set to them.