If you could be a little more clear on what you are doing I could help you out.
Based of your post.
1. when setting a mud bed on a slab you don't need a bonding agent. Just clean up concrete well with water and sponge then apply thinset to the concrete and put the deck mud on the wet thinset. But in all honesty, that would be over kill. Just pack the deck mud right on the concrete.
2. yes you do want to have 1/4" per foot slope. I make the pre slope atleast 3/4 inch think.
3. correct, pvc liner goes on top of the pre slope
4. the final layer of deck mud should be thicker than the pre slope.
Wall and Curb mud is not deck mud. It's call "fat mud" and is mixed with lime to give it more cling.
Hard to tell if your asking or give advice...