I kept and bred these crabs in a tank with a lot of coco coir for them to dig into. These guys don't crawl around on plants too much, but they appreciate picking at moss. They definitely like some shaded cover, so if you can put something with broad leaves like a peace lily in there, that'd be good. Some leaf litter for springtails to live in would help with an additional food source. Really, anything that works for dart frogs will work for these crabs. In my experience, they didn't climb much so flesh out the habitat horizontally, rather than vertically.
They really are super cool animals! Post some pics when you can.