Just off the cuff here, but I'm not sure that using a milk carton for a hide is a good idea. Milk cartons are generally wax-coated cardboard- which is soft enough to make it difficult (or maybe impossible?) to completely wash out, & milk, as we all know, can spoil, so I'd be afraid of such a container holding a bit of moisture + bacteria to which your new little friend won't have been previously exposed to. How will you even know if he defecates inside it? I'd find another cardboard box to modify & use, personally.
I'd also use a real (small) bowl of some kind for him to drink from. Water evaporates much more when it's spread out like that in the tray- that's fine for just adding humidity but I wouldn't expect him to drink form that- & you'd have to be checking it all the time to make sure it's not evaporated, leaving him with NO water, & all that checking will be stressful, for him, at least.![]()
Not so sure about the overturned bowl either- that's not an obvious place to dash for cover with no visual door. I'd modify a small inverted cardboard box, personally, or a plastic food container.
I'd rate your tub as "room for improvement"-(I haven't assessed the first photo yet.)