Wow! A bunch of questions. First you can raise any kind of chickens together. You can have brown egg layers, blue, green white etc. Each hen lays only one color of egg.
You will need a coop even if you free range. It should be weather tight without drafts. the chickens can stand a lot of cold but not wind or rain and definitly not drafts.
The chickens that lay blues and greens are some time called EE( Easter eggers). they are a mix and usually have small combs so can be reared in cold climates as can most hens with small combs. You may need some kind of heat for your coop. Or you may simply insulate the house to the extreme.
Yes there are some hens that have large combs and are cold sensitive.
read all you can if you decide to get chicks and prepare them a proper place before ordering any.
One book that is really good is Storeys Guide to Raising Chickens by Gail Damerow.
So may people have a lot of heart ache because they really were not prepared. Baby chicks are like human babies they need a lot of attention at first. It is not hard just getting things set up. Welcome to byc and I hope you learn lots from us all here. jean