You'll be fine with leaf litter. I kept mine with a thin layer of substrate mainly to help maintain humidity and then added egg crate for hiding places. Breeding was out of control in no time.
These will climb over Vaseline. I have read that really the only way to keep them contained is to have a sealing container with lots of small air holes.
Good luck keeping them contained =)
I had about a 4 inch band of vaseline and kept them in a gasket sealed box. Pretty much the only way I was able to keep them in lol. Any other way and they would just keep getting out.