1. Cotournix quail seem to be the best for meat--correct?
-> No, Jumbos and Bob Whites are bigger, but Coturnix are the tamest (I mean you can open the cage and just shoo them. Sometimes they may 'fall out'. My males also think it's a great idea to 'do the deed' when I am filling up the feeder, thus getting themselves, the female and whomever is around directly in my way into a pile of cooing feathers.
2. How well do they do in cold winter climates.
-> Exceptionally well. They are out in the coop with my chickens (-40C was the coldest this winter) without heat and they are still laying eggs.
3. Do they set their own eggs--hatch and raise their own young?
-> I haven't had one even pretend to try to go broody. I hear it's unlikely, but anything can happen. They are very independent once hatched from an incubator.
4. What type of housing/special requirements do they need? (for hot summers/cold winters)
-> 1.5 sq.ft. of space per is a good amount, I have a bit less than that per bird right now, and they look a bit crowded. So, a cage of 10'x1.5' would easily house 10 birds, it only needs to be about foot, foot and a half tall. They do not fly, do not need perches either. I do provide a light in the coop for supplemental daylight.
5. Anything else I might need to know/consider before ordering some?
-> Not really. They are by far the easiest bird to take care of. If you leave them water and food (I feed 25% cracked cord, 25% seed, 50% duck grower) they will lay eggs for you non-stop. After 6 weeks they are full grown and ready for a cull.
If you consider them for meat, expect about 6oz cleaned meat portions. The easiest thing to do is to skin them and cutting off of the wings (this way you have breast & legs left. I'd say doing it that way, you can go from cage to freezer in less than 5 minutes per bird.
Good luck!