Great frogs they are :-) Entertaining, active, and great facial expressions.
As for setup, they are tree frogs and should rarely be found on the substrate. I would recommend some Bromeliads and or Snake Plant for them. These plants give them places to climb, perch, and sleep. The Bromeliads also are self sufficient plants (Don't need soil to grow) and hold water which will aid in the humidity in the tank.
Also not a fan of gravel with WTFs since they are aggressive eaters and miss many a cricket. They swallow what enters the mouth and i have seen to many stone impacted frogs here.