Note one important item...the drain has weep holes in it that can easily be clogged while hotmopping. These allow any water that gets through the grout, cracks, etc. in the floor of the shower to run down the preslope, and down the drain. Make sure that those are clear prior to tiling. Don't know about the other questions, I'm not a pro. I guess, done absolutely right, a hot mop can work out. The people at www.johnbridge.com (a friend of Terry's) generally think otherwise. You could ask your question there and get some other opinions. I don't think that the tile association of America approves hotmopping, but I'm not sure. Doesn't mean it can't work, but it is not an approved method by that body. Your local inspectors are the final decision on what is allowed, though.