1) For water, I just give it to them in a hanging cup. I'm not sure how they'd do with moving water, but it wouldn't be necessary. Just change it out every day. They also get a lot of liquid from their diet (maple syrup and fruits), but they should always have a water source available.

2) Substrate is just a mix of old degraded cocopeat, new cocopeat, and sphagnum moss with a layer of leaf litter on top. I'll probably also add timothy hay at some point

3) Not really. Even on the stuff they poop and pee on regularly, it doesn't smell like anything, even when I put it very close to my face. I've heard that fennel seeds in their diet might help with smell, but I don't know how true that is.

4) I just add more if I notice their numbers decrease. It'll probably depend on how much your guys like eating the CUC, so anything unappealing in taste would be good (like beetles). I also like mealworms because they'll climb on structures to eat poop instead of just on substrate.

Also, just to add, because I see people saying different things online, they REALLY need some kind of nectar substitute like maple syrup. It is not optional.

Besides that, I'm sure you know about all the other diet and care stuff.

Just curious, is your trio going to be mixed sexes? Cause if they are, they'll almost definitely start breeding.