So far progress is going well. The floor tile is down, and all the backer board is installed in the shower. I did, however, run into a small problem with the backer board. The 1/2 inch backerboard was not quite as thick as the existing sheetrock because the sheetrock was glued to the studs and the glue added as much as 1/4 inch in places. To fix this problem, I added a layer of 1/4 inch backerboard on top of the 1/2 inch backerboard.
Shower with backerboard on walls:
Porcelain Marble floor tile: