As to the tiling flange, depending on how thick and high it is, and the size of the tile you are planning to use, you may be able to run the cement board up to just above the edge. You should install a vapor barrier behind it, and run that over the lip. If the tile will be supported by more than half of their height, lapping it over the filing flange without the cbu behind it will be fine.
There are lots of threads on Americast...use the search function for numerous opinions. No idea if anti-slip is a requirement. For help on tiling, check out www.johnbridge.com.