Maybe this is only good for ultralight, but I wouldn’t bring so many clothes. In fact, I’d replace a lot of the weight of the extra clothes with a good lightweight rain suit and an UL umbrella, if rain is your primary concern. I like Montbell’s U.L. Trekking umbrella, but I think a lot of people here use the larger but still lightweight GoLite or LiteFlex umbrella. The umbrella will also protect you from the sun, whose UV rays are brutal in that area of the world, right? I personally would bring 1 pair of convertible pants and wear them, so they shouldn’t count as your base weight. Pick the pair with the best water resistance, dry time, and comfort. If you’re worried about quality on a thru hike, can you mail yourself a different pair of pants to exchange at a halfway stop/town? Also, wear the hat and remove that from your base weight. Wear the buff around your neck, remove it from your base weight. I do this in hot and cold weather: in hot weather, I drench it at water stops and alternate it around my neck or my head under my hat. Mine dries quickly, so by the time it gets cold, I can use it for ear or face or neck warmth. I’d also only bring 2 pairs of socks. Wear one (remove that from your base weight), sleep in the clean ones, clean them both when the opportunity arises, mail yourself fresh socks regularly if allowed. If not, maybe three pairs of socks wouldn’t be horrible. I’d definitely only bring one sports bra, wear it, remove it from your base weight. Personally, I went with a super breathable and fast-drying bra called ExOfficio Give-N-Go Crossover because their Give-N-Go series washes by hand really easily, doesn’t seem to hold on to stink, and dries super quickly (but that particular model isn’t good for anyone over a C cup). This leads me to undies: bring 2 pairs, wear one (remove from base weight), carry the other, alternate them. I also wear ExOfficio Give-N-Go underwear so that at camp I can wash and dry the ones I’d worn that day and wear them when the next ones are ready to be washed. Plus they’re SUPER comfy.
This is probably the fair-skinned side of me talking, but given the extreme exposure to UV rays in that area of the world, I would opt for one high-UPF rated longsleeve shirt maybe with a hood that breathes well in the heat but can also provide a bit of warmth when it’s nippy out, and wear this as your only shirt. My hiking shirt is Outdoor Research Echo Longsleeve Hoodie, but this only had UPF 15. You might want something in the 50 range. Clean it at camp when it starts to smell, let it dry overnight if possible. Your sleeping baselayers could provide a back-up longsleeve shirt if your hiking shirt was out-of-service, or it could provide an extra bit of warmth with your hiking shirt. I don’t see the point in bringing so many shirts, personally, but you’re doing a very long hike, so it depends on your comfort. You’re going to stink no matter what. Definitely toss the flannel. Those are heavy. If you’re worried about not enough warmth with your down jacket, bring along a fleece top.
I would add some waterproof hiking mitts. I find it miserable to hike with your hands on your trekking poles, exposed to freezing rain and wind and water creeping up your arm sleeve. If it’s not super freezing, you can wear them by themselves, or if it is, wear your gloves underneath. I like my Borah Gear eVent mitts, but ZPacks also has a good pair. They’re long enough to cover the cuff of the rain jacket and they cinch down easily. I used to use a fleece-lined Mountain Hardwear pair I got from REI that served as both my gloves for warmth and water protection, but they got thrown in the dryer. Plus they were on the shorter and heavier side.
With so much rain, will you be bringing gaiters and/or waterproof shoes?
Last suggestion: since you’re going to the Icebreaker headquarters, stock up on all of your merino wool apparel there!!! I bet it’s a lot cheaper!
Hope my suggestions weren’t too extreme. Have a great adventure! That trail looks incredible.
