Hi Ozzy! Thanks for your advice :-)
I'll always bring bug protection if needed. Thing is, I know these mountains and they are not particulary buggy above tree line where I camp. There's a lot of cold wind that keeps them away, so that's why I decided to skip that.
Regarding rain gear... well to be honest I have never used my rain pants while hiking. I do like to get wet and my hiking pants dry quickly. It's just the psychological fear of being wet on a cold and windy night what keeps me adding that ounces to my pack. Also, I have put them at camp when it's very cold and windy, my hiking pants don't block the wind very well. I'll think about it, maybe there's another way.
I don't use the baselayers of my list while hiking. And maybe I can go without them inside my sleeping bag. However, around camp I'm not very active and tend to feel cold when temps go bellow 30F, worst if it's windy. That baselayer allows me to feel more confortable. Also, I think I might need them during daytime when we reach our goal (see below). Any suggestions?
Finally, you asked about our camp's altitude,
Camp 1: 9,800 ft
Camp 2: 13,800 ft
Camp 3: same as camp2
Camp 4: 15,000 ft
Camp 5: 13,800 ft
Highest elevation expected: 16,207 ft. Our goal is this peak (no technical climb required, tough hike though, we'll go through a glacier).
And before anyone mentions crampons and axes ... yes, that will be provided by our guides. I do not own that kind of gear, maybe in the future if I start doing more high mountain stuff. I live on a tropical country, to find some ice and snow, you must be really at high altitudes.