Just to throw in a though on the floor joist support and cutouts. Boxing in a set of joist is an easy way to get round some crazy plumbing angles. 2x10's with 16 " centers you can span about 15' so you can box in more than one set of joist. It would be a lot of cutting and if the subfloor is glued to the joist, it could be very difficult and may damage any finish floor above it. However, it should be doable for at least one set of joist where the toilet is. Google. "2x10 joist span chart"