I don't know the answers to your questions, but I do have a point to make. Just because a city freezes for the winter, doesn't mean that the planes have to be deiced. For example, FAI
is below freezing for half the year. But Fairbanks has a very dry and cold climate, which is not conducive to icing. So deicing usually only occurs at the beginning and end of winter. I'm pretty sure that the same occurs in northern places like Barrow, Nome, and Kotzebue. The south, which includes places like Anchorage, Bethel, Juneau, and the panhandle, has a much moister climate so deicing probably occurs more often there than the northern half of the state.
Bear in mind, out of all the times I've stopped in ANC
in winter, my plane has only been deiced once and that was in March. I've never been deiced in FAI
Semper ubi sub ubi.