The other thing with keeping them in the garage, I should have thought to mention before, is that it may be too busy for them. Every time the light goes on and off or the door slams or the car starts or your garage door opener hums and gurgles will be a stress on the birds. Stressed out birds can't be thrifty (lay enough eggs for how much $$ they eat), and if severe enough and frequent enough will decline in health. Quail are very nervous birds by natures since most anything from black crows to the neighbors cat to the usual wild predators. Another problem this causes for you is that they fly straight up whenever they hear a really loud noise or feel threatened. It's commonly referred to as boinking and is probably the number one non-disease related cause of death in adult quail in most cases. Flipping the light on when they don't expect it could leave you with a bunch of "special" quail all at one time.
If there is no other way, it may not smell bad if you keep it that clean but it will still smell like you're raising quail. Poultry and fowl have a distinct odor especially in a confined space. If I had to do it, I would make trays underneath their cages that would hold kitty litter, so you have something to mitigate the smell. The birds though, could not be allowed to access the kitty litter because they will eat it and I can't imagine that it is good for them. The same thing goes for shavings really.
Outside a rabbit hutch with 1/2x1/2 wire mesh all around would be completely sufficient as long as you get one with a low ceiling or pad the ceiling in some way. During the cold months you'd need to wrap the cage in plastic sheeting to block the wind. You don't need or want to provide healthy adult quail with auxiliary heat since they will grow down sufficient to the weather they're kept in and could die if heat went off due to power loss or such.