I used paper towels for substrate.
They do poop a fair bit and it just made cleanup easier. I wiped down enclosures and changed substrate every 2 or 3 days.
Also I was breeding and wanted to control where they laid their eggs, so I used 5" pots for the pothos vines and that was the only soil so they always laid in the pots. (Actually I had an inch or two of peat moss on top of the soil in the pots and this layer is where they dug and laid). It was easy to tell when a group had a female lay because they would toss dirt out of the pot onto the paper towels when they dug their shallow nests. This made egg collection easy to do and easy to know when to collect (I had about 20 trios going).
For food, I just used a couple of the commercial foods for crested geckos. Worked great for me, and I'd recommend it. Babies grew into breeding healthy adults on the commercial diets no problem. If your friend wants, occasional crickets or other insects, well ripened fruit, a little honey will all be appreciated for treats.
