I'm putting a bathroom in the basement. I need to have sub-floor in so I can install a tub and tile the floor. I was either going to use Dricore, or 5/8" OSB laid on top of DMX and fastened with tapcon screws. I read that Dricore isn't recommended for use under tile because of how much it moves, but what about the OSB/DMX?
I assume your floor is concrete in this case. I would use a decoupling membrane like schluter ditra or one of the competitors. You can thinset this directly to the concrete and then tile on top.
For the tub I would just use a mortar bed to support the tub and then attach the flange to the wall(s)