I hiked SOBO in 2011; each year and direction and certainly path choices are different, but ...
Your choices seem like very intelligent ones to me.
A 14 oz down jacket seems heavy; yes, there's a lot of snow, in either direction, but I brought an Montbell EX Light down jacket at 6 oz, plus a Montbell thermawrap vest at another 6 oz, and those did me fine as warmth layers, no fleece or anything else. The vest was good as I could hike in that when it was colder. I didn't use a windshirt, as my lightweight rainshell did double duty there.
Long underwear (bottoms) --- my gear list says I brought a 5 oz capilene 1 pair, but I don't recall using them. Maybe in the snow in Montana a time or two. Once you get out of major snow you can certainly mail that home, however.
I would not be inclined to bring a solar charger. If you own it already, however, and are going Nobo and can attach it to your pack ... then maybe. But I bet that at some point along the way you'll decide to mail it home. Resupply isn't really THAT much different than on the PCT. Longest carry I had was 8 days.
Microspikes and goretex socks --- yes to both, I suggest, until you're mostly or entirely out of snow.
Ice axe, btw? Might need one. What I did was bring a "whippet" self-arrest pole as one of my two poles, and then when I got out of snow I mailed it home to swap with a normal pole. The whippet is a bit heavy for a pole, but nice to always have your self-arrest pick deployed, and I did use it once in Montana, in GNP (though perhaps I could have arrested myself anyway, dunno).
Don't forget bear spray. If you're NOBO you can have it mailed to you, perhaps somewhere just south of Yellowstone (Atlantic city maybe) and at least by then you'll be in shape that the extra weight won't be a big deal!
You going with just Ley maps? I suggest adding Yogi at least. You can load yourself with paper on that trail, and I did --- Wolf too, and Bear Creek maps, and Delorme atlas pages ... do make sure that you have the latest gpx for the track (or if possible, trackS to include purple alternates). Navigation is indeed a bigger factor on the CDT.
Best of luck on your journey!