A.K.
Have you thought of a litter maid litter box? that way the treasures are hidden and the kids can't get to them, the only thing they could get to is the litter and I don't think they would want it if there were no treasures. Also, have you thought of putting a pet safe door in the closet or wall of the closet so the cats can get in and then you can close the closet doors so that the kids can't get in? Also, since your cats can't jump, maybe you could put a baby gate up but leave room at the bottom for the cats to go under but not enough that the kids can? I hope at least one of these ideas helps you.