Flooring Tile - How level does the concrete slab need to be

I am installing both ceramic tile and granite tile in 3 areas in the basement over a concrete slab (bathroom, walkout area, wet bar area). When I laid down the tile, I noticed the tiles rock and are not flat against the concrete slab, although some are. Most areas are about 1/8" off, but by the corner of the sliding glass door where the door meets the exterior wall, the cement is raised up about a 1/2". I plan on chipping the concrete in the corner and use self leveling concrete (SLC). In this area I had the granite and tile cut to form a half circle that will be installed in front of the walkout door. How should the forms be built to contain the concrete within a half-circle pattern?

In the other areas that are off by ~1/8" should SLC also be used or can mortar be applied to accomodate the differences. I also plan to use a membrane before applying the mortar, could that be used to help level the floor?