Hi Anna :) You do not want to let them out of their coop. They will run and fly, most likely never to return. You also can't keep all 12 of them together, unless you build a large aviary or similar. Males are prone to fighting, if there are females around. Apparently they are monogamous, but I keep both pairs, trios and a group of a male and 3 females. In cages, I wouldn't recommend more than a pair, I small aviaries 2-3 females and a male should be fine. Perhaps try that craigslist-thing I keep reading about on here (assuming you are in the US), to see if someone has a single pair or similar you can buy?
On this forum, people usually say buttons can't handle cold temps, but I live in Scandinavia and I kept most of mine (9-ish birds, I think) outside in an unheated building all winter with 0 casualties. I estimate the temps went down to 14 F several times - at least their water froze often enough to be annoying. Perhaps the Scandinavian birds are more hardy than the ones in the US, or maybe the US keepers are just babying their birds too much ^^
If you keep them outside, just make sure they can get out of any wind, draft and rain and if you are worried, perhaps you can give them a heat lamp - but if you do that, they won't get the feathering required to handle the cold, so if you loose power, this can cause them to die.
Purpose in production? Well.. The first ones, I just got because I thought they'd be a cute addition to my budgie aviary. Which they definitely were. Then they started hatching their own chicks - something that apparently rarely happens - and I started selling the chicks. They still hatch their own chicks and selling the chicks makes more money than it costs to feed them. I can sell the hens for something like 10 dollars and the roos for around 3 and a 15 kg bag of gamebird starter costs 13.5 dollars and keeps all of my birds (currently 17, but I have 6 chicks that are ready to be sold) alive for 4 months or so. So selling the 6 chicks I already have should pretty much feed all the birds for a year and I have two more hens that are broody and expected to get chicks any day now.
Occasionally I'll eat their eggs, but they really are tiny. And I think they taste just like chicken eggs, though they are supposed to be more healthy. You can eat the birds as well, but I think they are supposed to weigh 50 grams or something like that when they are alive, I can't imagine you'll get enough meat to be worth the trouble of slaughtering them.
If you want quail for meat and eggs, go for coturnix. If you want quail for cuteness, go for buttons. If you want quail for beauty, go for the Californian ones. I only have buttons, so I can't tell you much about temperament, but the coturnix should be calmer than buttons. Buttons don't replace chickens, their eggs are simply too tiny. But imo they are much cuter than chickens :)