Bare bottom is fine as long as the babies have a tank of their own. You may lose a few more to cannibalism than you would in a tank with hiding places, but CPOs aren't as nasty as most Crays so you should still raise a good % of them.
Sounds like a good plan - best parameters for the babies to grow is; 80degF, 7.8pH, GH/KH of over 10 degrees. (GH18, KH12 is what I raised mine in)
Make sure there's a lot of hidey holes for the babies - I lost over 12 from one birth to fighting over territory (3 less hiding spots than babies)