Mine also lives in an unheated barn, usually closed at night, but often left open during the day regardless of temperature of precipitation. I didn't have any problems last winter, and not planning to do anything different this year either.
This has been largely my experience too. The e-moto's have received a polarized reaction, people are either totally enamored with them, or think they are the dumbest idea ever. No middle ground it seems.
Alta's aren't bothered by temps into the 20s, I just finished the 24hrs of starvation ridge and we had night temps in the 20s, with no loss of performance.
Hope that answers your questions about cold.
That's some awesome trails there, nice mix of tight tracks and more open forest. But as you say, likely the last warm sorta snow free day of this season.
Thanks for sharing!