Well, my nephew did climbing expeditions into the high Arctic, Patagonia, the Karakoram, and Himalayas, often months at a time in below zero conditions, and the question of film rewind or even camera winterization never even came up. No shots lost. And I've known my share of famous high altitude mountaineers who funded their expeditions largely by pictures (helps to have some sponsor's gear logo somewhere "accidentally" in the frame, on a jacket, tent, or ice axe etc); And they didn't even discuss that kind of issue. Staying alive was the greater priority.
But there was a general consensus about camera gear. Don't go motor-wind. And the less electronics and more manual a camera is, the better. Batteries can get cold and useless. Too many bells n' whistles is just asking for trouble. If you can go the film route rather than digital, do. It's more reliable in extreme conditions.
I've photographed in the mountains myself innumerable times, but never under those extreme conditions. But a blizzard even at 12,000 feet can be cold enough, and I can hardly count how many of those I've been in too. For most of my adult life, I shot large format sheet film, which is a somewhat different ballgame, but will still get the skin of your fingers stuck to anything metal if ungloved in low temps. One eventually learns the necessary tricks; often the hard way, however.
