Thank you very much! We met with the contractor yesterday and the plan is: *Tiling walls: We will tile around the toilet and behind the vanity as well as on that right-hand wall. I think it would look odd if we didn't, and it is a splash zone of sorts, right by the tub/shower. *Tile height on the walls: We decided on 40" because the vanity will be 36" high and that will allow for a 4" backsplash. *Melle - isn't that iridescent tile crazy? RE the vanity, I'm sorry to hear that about the Godmorgon. Ours, the dark black/brown color, has regular handles, not integrated ones. I wonder if that will make a difference? We are going to purchase the Godmorgon high cabinet as well - it is only 15"W by 11"D and so will occupy little floor and visual space. *RE toilets: Maybe you are right that I should re-think the comfort vs. regular height question. But don't family bathrooms usually have regular height toilets? I'm thinking of resale value down the line too. Thanks!

There is no such thing as a shallow P-trap, what your looking at is a "closet bend", which is simply a long radiu 90deg elbow.... IN Plumbing vernacular what you call a toilet is properly called a "water closet" and the round ring on the floor that the water closet is mounted on is called a "closet ring". From your description your closet ring is mounted directly on the top end of the closet bend, which is fine. If the drain line was deeper they could put a length of pipe from a closet flange to the closet bend, but in your case its not needed. Not only is there NO P-TRAP on the line, code prohibits installing a P-trap there. For a water closet the trap is built into the bowl section of the water closet and if one was to install a P-trap on the line, that would be double trapping which is code prohibited. The bottom line is,,, the answer to your last question if "YES", you are worrying for nothing.

Definitely check the specs before buying anything. The last wall-hung toilet I had installed needed a 6" stud space, and the wall needed to be rebuilt so it was beefy enough to support the carrier bracket for the toilet.

Not a plumber. Remember that you will need a wall in the level below your plumbing through which to run a drain pipe; therefore, if you can rearrange the fixtures and reuse the existing drains, that is going to be your most practical way to go. A vanity can hide pipes that need to be affixed to a drain not directly beneath the sink so moving a vanity and possibly using an existing sink drain for a toilet is something to consider. Turning a tub w/shower at a right angle, and still reusing the existing drain is also often a practical option as is moving a closet. In lieu of two separate bath rooms, you might consider creating a single "bath and a half" with three sections with doors between them -- one oversized bath/shower combo between two powder rooms. (Most families tend to avoid running both a shower and tub at the same time because of water pressure and hot water issues.) You might also consider closing that "open to below" space at the top landing of the stairs in order to add upstairs closet space and enable you to utilize existing closet space adjacent to the existing plumbing to enlarge and/or remodel your existing bath into a bath and a half.