This!
Circumstances and management styles vary and benefit from different practices.
I was able to take advantage of natural air circulation patterns when designing Neuchickenstein. Not everyone has those patterns.
I wouldn't know. I'm a big believer in passive ventilation because I would be more likely to have power outages in hot weather than cold weather (barring the occasional ice storm), because we get hurricanes.
Are those fans rated for barn use?
If not, they're a fire hazard due to the buildup of feather dander and dust from the bedding. :(
Other than that, your modifications ought to help. The ultimate test is whether or not the temperature and humidity are the same inside as out. :)
Draft-free means no wind strong enough to ruffle feathers while the chickens are on the roost. Look at my outdoor brooder: https://www.backyardchickens.com/articles/run-to-outdoor-brooder-conversion.76634/
I remember those mountain winter winds from when I lived in Boone. You might want to tarp...