Thanks Steve, and thanks for all your posts! We were reading them religiously in the days leading up to our trip.
Ah, I didn't realize that was the old trail until I got on the forum again today and saw so many other people mentioning it and put two and two together. Really liked not getting my feet wet so early in the hike, though on the way back down I was thinking this portion of trail was much rougher than other switchbacks along the way.
They went up the shallower bottom part of the chute and then cutover to the switchbacks. They got a little ways up the first portion of exposed cabling or so I think before deciding that portion was too dicey as well without ice axes, and turned back.
And about the sun dropping behind the crest and the chute icing up, that makes a lot of sense! It looked so easy in the morning we assumed it would be similar when we got there. Lesson learned!