I've seen some reports from Aconcagua where peope claims that base layer + softshell wasnt warm enough and that the winds were harsch. Even read about frostbite at the lower part of the body.
In that case I wonder if it's enough to add a hardshell to block wind more than what the softshell provides, I.e
Merino base pants
Softshell pants (midweight)
Hardshell pants or bib
... and just add puffy on top of it when resting/stopping/in case of injury etc?
Or is it better to go for something like
Merino base
Puffy
Hardshell
... and skip the softshell competely and just try to ventilate puffy+hardshells according to activity?
My experience from summit nights are that the pace is really slow (6000m peaks) due to altitude/heavy breathing, so that decreases body heat generated by activity.
Not speaking about ice climbing tho, more like normal walking and maybe just easier scrambling.