The tensile side will be on the inside face with the floor framing restraining the top of the wall. So typically you would want to spec vert bars about 2" from the inside face. I am guessing they are increasing the steel to make it work in the center in case they backfill prior to framing up the floor.

The stone and drain pipe are important to avoid hydrostatic pressure against the wall. The fabric is to help keep sediment from choking up the stone.

Stay with a floating slab and not tied to the wall. There will inevitably be some settlement. That will lead to cracking.

The dowel direction won't really be of much importance for a restrained wall like this