In reply to Stani49:
First of all, my recent trip was aiming for peaks of just over 6000m in the Andes so lower than you and not the same area, BUT our kit list was the same.
Midlayer fleece: I took 2, a marmot one that was polartec 100 weight, and a slightly thinner Haglofs fleece that I didn't wear, not because it wasn't warm enough, just didn't get round to it and it stayed at base a lot of the time.
Fleece jacket: I wore my vapour rise.
Climbing gloves: ME Guide gloves, I took that to mean winter climbing gloves.
Thermal gloves: silk liners
Trousers: daren't really advise as such, since as I said to start with, different area and slightly lower altitude, but on cold summit days I was (just about) fine with Patagonia winter guide (same as mixmasters) over cheap thermal Peter Storm leggings.
Maybe the above is a little help? Can you speak to your expedition leader to see if what you have is suitable?