Q1: I've received multiple, conflicting reports... Some say put wonderboard over greenboard and others say you can attach the wonderboard directly to the studs. Which is it??? Which is preferred?

Staple a vapor barrier over the wood stud, leaving space between studs for ventilation and then attach the wonderboard to the studs. ( If you put bisqueen around the enclosure, and then cut out between the studs, this would prevent the wonderboard from getting the wood wet, and the openings between the studs would allow the back of the wonderboard to dry)

Q2: I had to tear out the tile (over mortar) floor to repair the subflooring in my bathroom. I plan on replacing it with vinyl sheet flooring. My problem is that the toilet flange now sticks up an inch higher than the new floor. Should I find a way/pay a plumber to lower the cast iron sewer pipe or build a 1-inch "pedestal" for the toilet to sit on? Any suggestions?
Thanks a bunch and a speedy answer would keep me working over the weekend. -Lyle

I would add more thickness to the floor before you lay the vinyl. If you look underneath the toilet, you will note that there is room for the flange to set higher than the finished floor. Not much, but some.
Terry

• Installing Cement Board on Walls and Ceilings