Thank you for your help everyone. I've started to narrow down a few items on the list, but I'm just as confused on others. Here are some updates and more questions.
1. I updated the gear list and reposted it. As it stands, excluding a bear canister, ice axe, crampons, and any worn clothing, it comes out to precisely 14 pounds. Not as light as I'd like, but perfectly comfortable the way it looks now. I expect that my estimates are a little conservative and that the weight may come down by as much as half a pound once I get more accurate measurements (hopefully). That said, I'd like to bring it down even more if possible.
2. I purchased a down jacket here on the gear swap forum. Got an Eddie Bauer Downlight Sweater (new) in M-Tall for $55. It fits perfectly and I couldn't have gotten a better deal.
3. Discovered, thanks to reading the thread, "A New Paradigm for Understanding Garment Warmth" that Polartec Power Stretch is a lot warmer and lighter than Patagonia R1, so I'm looking to use that for my bottom baselayer. I think that's a great find, I wouldn't have expected that result. I still want to bring the merino longsleeve crew since I expect to hike in that at times.
1. Packs -- I'm still totally lost here. If my base pack weight stays at 14lbs, and if I carry about 1.75lbs/day of food with roughly 4-5 days on average for resupplies (optimistic?), and carry roughly 2-3 liters of water at a time through WA/OR/Sierras (also optimistic?) that works out to roughly 25-28lbs on the low end of fully stocked. I would consider 25lbs or so the "average" weight that I'd expect to carry on any given day.
If the longest necessary time without restock is 10 days in the Sierras (a guess based on anecdote, could possibly be less?), adding in the bear canister, that is about 34lbs (keeping constant amount of water--I'm guessing here again, as I've done most of my hiking in New Zealand, Michigan, and the Wind Rivers where water is usually plentiful). I'm guessing it would be about the same with a pack full of extra water rather than food (through the desert). So the upper end of what I expect to carry is roughly 35lbs (could approach 40lbs max in practice, who knows).
Essentially, I'm facing a great deal of uncertainty about my "true" pack weight given the gear list that I have. It could be around 25lbs under good circumstances, but I could be carrying as much as 35lbs as well. Can anyone give me an idea of what a good estimate is based on my base weight? I was almost sold on the Osprey Exos (leaning towards the 58L, but unsure of whether or not that's too much volume). But now I'm not sure--I don't know if it will be able to carry those higher weights comfortably, and the pack itself is not really as light as I had hoped (2lbs 10oz in 58L size large). I'm looking at the whole gamut of Granite Gear packs (Nimbus Ozone, Nimbus Meridian, Vapor Trail, Escape AC60) based on their reputed comfort. I am also considering a ULA Circuit, and pining after the thought of carrying something along the lines of a GG Mariposa Plus or ULA Ohm (though I think my list is a bit heavy for these packs).
I think my only recourse is just to order a bunch of packs, load em' up, and see which one is most comfortable. In case your eyes glazed over when reading the above novel, here are the Spark Notes: I'm looking for the most comfortable pack possible, something that is capable of carrying a maximum of 35lbs, but also something that can make 25lbs feel nice and light. Again, comfort is my main concern here, and at this point, I'm willing to go up to about 3lbs-3.5lbs or so to get the most comfortable pack possible (I have traumatic pack experiences--Gregory Z55 and a 110L (!) NOLS pack which reached a max of 80lbs--while hiking off trail).
2. Shoes -- Also more or less lost here. This is complicated by the fact that I want to go southbound. Do I need crampons for Northern Washington? What about GTX for the snow? I'm skipping GTX for the rest of the trail obviously, but I was thinking about something like the Vasque Velocity GTX for extra traction and stuff for the snow, but maybe that's a bit much. Any other recommendations? Yea or nay on the Vasque Velocity/GTX?
3. Rain jacket -- Seriously...huge fail. I wanted to use the Marmot Mica or TNF Triumph but they are way too short. Center back length is 28" for Medium. I have a Marmot Aegis with a center back length of 28 3/4" and it's too short for my torso. I may need to just splurge on this and get a Super Mica which has a longer torso--but it's heavier and more expensive than I would like. Any other options for me (long torso, low budget)?
Sorry for the long post, this always seems to happen.