this is a topic I can dig into because I just got back from a gear test trip on Quandary in which the temps were down to 5* at night with 30 MPH winds. Making it freakin' cold.
The biggest suggestion I have is to get out with your gear as much as possible in the coldest and windiest conditions you can before Elbert.
I had several pieces of gear fail for me on my trip-
1. Headlamp - I had the BD Gizmo with AAA batteries that quit working almost immediately. The button to activate the lamp got stuck. Alkaline batteries didn't cut it. I had to borrow a headlamp to get my tent up. I was told by some experienced winter campers that they always carry two headlamps with lithium batteries. I need to look into a headlamp that is built for extreme weather because I really wasn't expecting the BD Gizmo button to get stuck. Fortunately it was a full moon night, so a headlamp wasn't necessary for most activities.
2. Tent poles - I had the new ultralight Easton tent poles which did hold up to the winds, but did not like being taken apart in the cold. One of the connections came apart. It's hard to be slow and careful when it's freezing and the wind and snow is blowing, but I would recommend that you be very careful with your poles when taking them apart in those conditions.
3. Jetboil- Another surprise for me, but the dang thing would not light in the morning when I needed the hot water the most- and this was even with me sleeping with the canister in my sleeping bag all night. I set the canister out in the cold for only a few minutes, but I guess that was enough to mess it up. I read on the Jetboil instructions that you are not supposed to use a windscreen, so I didn't bring one. I would love to hear others suggestions about using the Jetboil in extreme conditions.
4. Glove layers- I didn't have enough protection here. I was carrying smartwool liners, OR mid-layer and OR Gortex shells. When climbing Quandary, the winds picked up, and even with three glove layers, my hands still got cold. The problem came when I had to switch out layers and expose my skin to the elements. With the windshield my skin started to immediately freeze. So my recommendation would be to avoid exposing your skin at the higher elevations as much as possible- keep that liner on at all times. I made it up to 13,000 but had to turn around due to my hands alone. I just bought the Defeet liners that Skurka recommends- they have stickies on them, so I hope I can keep them on at all times. But, I may move to mountaineering or heavy duty ski mittens if I'm expecting to be in those conditions again. Cold hands can really ruin a trip.
I looked at your list and i was wondering what you will do to keep your water from freezing? I bring Nalgene bottles because I have insulating covers for them. I also just read about people burying their water bottles at night in snow to prevent them from freezing (except in the case when you think it will rain, not likely in Colorado this time of year).
Also, in regards to your down insulation layers- I have a RAB Infinity jacket which performed AWESOME in these conditions-I had to throw it on everytime I stood still. I'm not sure your Patagonia would provide enough insulation. For my bottoms- I went with the inexpensive military pant liners that I threw over top my other layer for around camp and for sleeping- They were great. I have an extra pair of the military pant liners in medium long that I could send to you if you want to try them out. Of course, down pants would be lighter, but they are so expensive.
Let me know if you want to chat on the phone....I really love geeking out on this topic!