Response to #1: I expect to butcher 12 meat birds by the 4th of July (approximate date) and I am not anticipating replacing them immediately. (This may change) Would you still separate them?
Yep, I would still separate them. Even if this is the only time you will have meat birds.... because it will make tending to them much easier. They should be on a much higher protein than your layers, so it will be nice if they can be fed separately. Also, tractors are great. They are great for a broody, raising replacement chicks, keeping a trio of birds to get pure bred eggs, or to quarantine new stock.
As to snow and wind.....
For snow, use steep roof angles! I hate having to shovel roofs. The snow, if humid enough to stick to the bird net, is going to be a problem. If your snow is infrequent enough, since you are home, you can just go out and shake it off as needed. I hate that too though.
I ended up doing strong wire tops on the secure runs that can handle snow load. I use net for the "no snow" season over my less secure runs.
As for wind, use wind blocks. The clearish plastic or fiberglass or whatever roof panels can also be used on walls with enough support. They are a good option to keep light in the run, but block the wind. You probably only need 1 or 2 solid run walls to block wind.
Electric is great for lights, and for a way to heat water. Motion sensor lights all around the coop would be great for bear and wolves.
For bear, yes, use electric wire. You shouldn't need that many electric strands around the fence (1 towards the bottom, one at nose height, one a bit above nose hight), if you bait the strands to teach the bears. Usually bears have a route that they take... bait the fence closest to the bear path. Tinfoil crumpled all around the wire and coated in peanutbutter is good for bears. Not sure what the best bait for wolves would be, to help teach them the fence.
Because nasty weather means poultry hate going outside.... I have found 8 to 9 square feet per bird is how much I need of snow free space. So.... double-ish the recommended 4 square feet for coop space.