Hmm, I thought it was just cross beams marking where the pop door went. But they look nest sized... Might need OP to confirm if that's what we're looking at?
So here's one issue as far as roosts... birds want to roost higher, and with the height of the nests, it's going to be tough to put bars any higher than the nests (as you need headroom and room for draft to go over their heads. So you may be fighting to keep birds out of the nests at night...
Well, no, you might not. Now that I read this again, you're intending to put 18 birds in a 32 sq ft coop? Recommended minimum is 4 sq ft per bird and you're at 1.77 sq ft, assuming NOTHING is taking up any floor space (nests, feeder, etc). Some folks can get away with tigher quarters if the...
Photos of build? I'd really consider eliminating some of those boxes, especially if any of them they eat up valuable floor space. You only need 1 box for every 3-4 birds.
Are all the chicks going in this coop or your son's GF taking some with her?
Rather than put the heat lamp inside it'd be...