(NB for some strange reason, when i clicked Edit it looks OK, but when posted the pics and parts of the text are coming up in places I didn't want them to, different than in the original, so I hope you can sort it out, I've given up, sorry. The two pics of the plastic cage are of the whole and of part of the floor space.)
Wow, what an exciting weekend ahead! Do post some pics when they've settled in.
Like you, i'm a real newbie to quail, so perhaps with luck someone will come on and give you more experienced advice on stock densities etc. I've preferred to start by giving mine plenty of room and then building up when i've found out more about how they get on. At present i'm working to 1sq.ft per bird, and have 2 guinea pig cages in use, both about 2X3ft. The wooden one has been adapted into 2 layers, a bit like yours, initially with ramp though i didn't use this as i found the top part, with the large animal sleeping compartment, was darker than the bottom, and so i just put 4 in the bottom part and the other 4 in the plastic cage.
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Just to show you what 4 look like in 2X3ft, this is the plastic cage, 2X3ft, with an open-fronted cardboard snuggle box (no pophole needed.) plus feeder and quail-sized dustbath.
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and this is the plastic cage with the snuggle box.
When my new cages are finished they'll be 2X3 ft and i shall aim for 1 male + 3-5 females in each. I expect i could put more than that if/when i breed some young ones, and i know lots of people do keep quail at much higher densities than that, but i prefer to see tham with plenty of room to enjoy their busy little lives.
As for your friend, if it were me I'd say to him that you haven't got room for 'many more until January'. For one thing, this is obviously true, and also I expect you'd rather just feel your way with just your own new birds for a few weeks, especially as we're going into winter now. It wouldn't be a good idea to mix his with yours in any case, and you couldn't take on two or more males as they would fight. . Maybe he can get a second hand cage, or even use a large box with a mesh top, indoors somewhere? Anyway, that's his problem!