Welcome!!
I LOVE that house for quail, and it will be just fine for five. They will be happy quail! I wouldn't worry about the top portion not closing off--they probably won't use it much anyway. They really prefer to be at ground level, and not closed in if they can help it. And if you want a boy--get one. They're funny to watch, and have an adorable little crow, and I think they do tend to be more "friendly" if by "friendly" you mean approachable--they are less timid than the females, so they will tend to be less terrified of people.
I keep seven coturnix quail in a 10 foot x10 foot enclosure, which people tell me is way too big but trust me, they are very very happy quail. I am not interested in maximizing my space for the largest number of quail. I just want happy quail, and that's what I have. The nice thing about a larger enclosure (with fewer animals) is it doesn't have to be cleaned very often (mine, not at all--nature does the cleaning), and the birds are less stressed. They don't fight if they have enough space, because the less dominant hens will just run away from the more dominant. The females don't end up with feathers taken out of their heads (like most females in a wire brooder set-up) because they can escape the male's advances if they're not interested.
Mine are on dirt & straw & grass, and they have honeysuckle and Virginia creeper for cover. Also, a bale of hay that they have dug little holes under for dust baths (I propped one end up a bit to give them a start, and they've expanded the "sheltered" portion). There are logs and other bits and pieces that offer naturalistic cover, as well as two large dog houses for getting out of the rain and to protect their food from moisture. They use the doghouses to eat in (because they have no choice), but they never sleep in them. They would rather hang under the eaves instead when it's raining, and in the open when it's not. If I were to do it again, I'd just make open-air shelters with roofs and no--or only one--wall, or little lean-to style shelters. On the other hand, they haven't been through a winter in this set-up yet, so they may use the houses during extreme weather.
One concern with your set-up is that some predators may dig under or try to up-end the containment. Make sure it's too heavy for a raccoon to lift or knock over with their body weight (is it top-heavy?). You can keep predators from digging under in a variety of ways, but probably the simplest is to fashion a "skirt" out of wire around the bottom, sticking outward. Digging predators won't bother if they have to begin digging from two feet away, and obviously they can't dig through the wire skirt.
I have ducks, chickens, quail, goats, and a cat (and honeybees). If you don't count the bees, the quail are by far the easiest critters I keep. I put food and water out for them, and I can go away for a week or more without incident and without help. But I love to toss them bird seed (a favorite treat) each time I go out there, and they get really excited when they see me coming.
Good luck and enjoy!
P.S. Just realized you plan to put that inside a larger enclosure... so you won't need the wire skirt.
