Try putting in a waterbowl that "sink" into the ground (and that is fairly deep)- They like to splash in it when you are not looking (saw it with my own eyezzz the other day, was quite weird).

Feeding should be once every week or once every two weeks, with LOTS of roaches as cascade mentioned. If you are using dubias, the dubias will burrow, but that makes a nice snack for them once their tunnels have been set up! I have so many roaches in my tank, I might as well put food in for the roaches too

You most probably won't ever see them. But don't stress, if you keep them in the dark and use a torch, you'll see legs sticking out of the burrow

Also, you will see that one or two of them will grow faster than the others. Only start worrying about that once they reach maturity, LOL. I've got a matriarch in my communal, she'll probably chow the others once she matures, but that's life I guess.

I've had my communal for a few months now and I haven't had ANY casualties (and I've rehoused them twice).

Good luck!

I have put in a water bowl, the pics were taken just after I put them all in the enclosure.