shower install

Hello there. I am re-doing my shower. I have it ready to go and hve researched it alot. Its just bare frame now. Its 4' x4' wit a seat at 45dgs in one of the corners. Interested in kerdi and was at jlc live yesterday. Schluter guy told me no need for rubber membrane with kerdi. Just 1 pre sloped mud and kerdi on top. What do you guys think. What about the seat. Do I need to mud it or is durock pitched sufficient wit kerdi on top, smae question with the curb. I'm also tiling the ceiling. Durock and kerdi again?. Do I need thinset on the ceiling for applying the tiles. Alot of? S I know but dont want to rip it out in a years time. Thanks

If You are not very experienced with tile, The Kerdi products are great, they have pretty easy to follow instructions and even plenty of videos on the net. They are pretty much made with the correct slope already in them, just dry fit and check with a level first to make sure the water will drain.
On the ceiling, I have used both Mastic and Thinset, Just make sure you use full trowell notches and press the tile into it very very very well and wiggle it a little bit because it's more the suction created by the notches that will hold the tile up until it dries. Once the glue or morter dries, then the setting material actually holds the tile.

That makes sense for the ceiling. I cant use thekerdi base because of the seat in the corner runs from the floor up 2'. Otherwise I would, it looks alot easier. I am concerned about waterproofing the seat. Should I just kerdi everything?