Nice!
I had a loophole for my in-town flock in that "temporary" or "portable" structures didn't have to obey setbacks. My Little Monitor Coop has carrying loops built into it (slide a pair of 2x4s through them and it can be carried by 4 men), and the original attached run was designed to be...
That's not terribly cold then. I've had my birds do just fine in my open air coop down to 10F this winter (unusual cold for my area). 10F in Central North Carolina in an Open Air Coop
Make sure that your roosting area is well-protected from drafts and that they have excellent ventilation above...
You don't need to worry about keeping heat in. In fact, by cutting off ventilation attempts to keep heat in become counter-productive since an ill-ventilated coop gets damp and dampness promotes frostbite?
Keep the chickens dry and out of the wind and their built-in down parkas will keep them...
Good luck with your build. You've obviously put a lot of thought into it.
Do you have any ventilation plans other than the one window in the middle of the wall?
Repecka Illustrates Coop Ventilation