I definitely would not go with Silkies or Bantam Cochins if you want free range foraging.
I have a heavy hawk area, and the only way I can keep those birds is under heavily netted and reinforced coop and run. They simply cannot run fast enough to avoid a predator.
I would go back to the drawing board and rethink your options.
I have heard good things about Egyptian Fayoumis and games for foraging and predator savvy.
Buckeyes are cold hearty, congenial birds, that forage well and are good at gleaning bugs and pests. Keeping a rooster can help the flock be more savvy to predators. (Not that you indicated interest, but Buckeyes are great for the table, so you could eat your extra hens and roosters as needed).
Most chickens, if started in the coop (locked in for a few days) will return to it each night, though games can tend to want to roost in trees.
You can also look at this handy chart for chicken characteristics. I would stay away from any heavy footed breeds, as that makes for slow runners, and any with really large combs, as that can make them more vulnerable to cold.
http://www.sagehenfarmlodi.com/chooks/chooks.html
https://www.mypetchicken.com/catalog/Baby-Chicks/Egyptian-Fayoumi-p1260.aspx