you'd love the western side :)
i always bring a north face down 0 degree bag, when it's as cold on a trip as yours, i'd wrap it with a bivy and be sleeping in my clothes most likely.
dual purposing equipment is one of the best ways to shed weight, along with dropping heavy items ... i have a simple rule, each time i return i evaluate every item i didn't touch the entire trip and ask if its essential.
from there i categorize by season, and sometimes i've been cold (not life threatening, but definitely miserable).
as i've aged, i've become accustomed to bringing an extra jacket, but most times its a security blanket rather than a necessity.
but as you well mention, it only takes one mistake to truly mess things up.
really enjoyed your photos, jeff #happytrails