PCT Thru Hike Clothing

If the rain jacket is actually waterproof then it must be windproof as well.

Ditch the windbreaker (or the rain jacket for socal if u dont mind hiking wet in rain). i usually just bring a rain jacket and hike in rain without it (unless its cold), then change into warm dry clothes at camp. I then use the jacket for chores etc. i sweat like mad in my mica while hiking so it is semi pointless to wear while hot and hiking in rain. The plus of hiking in a windshirt is that you wont sweat like mad.

Ditch the extra underwear and shirt. Go 1 sunshirt shirt for day 1 thermal for night imo.

I reccomend darn tough merino socks. 2 pairs total. Switch out every day. Wash underwear and socks given opportunity. Wear underwear to dry it. Pin socks to pack to dry them.

I thru-hiked in 09. I had a Houdini and a rain jacket and would bring both again. Getting sweaty under your rain jacket sucks, and the Houdini is amazingly breathable–I wore mine all the time on the trail. Also, if it's really cold (which it will be at some point), you can wear the houdini under the rain jacket for a bit of extra warmth.

I would ditch the zip-t (use your houdini/rain jacket for extra warmth during the day; sleep in your down jacket if necessary). I'd also ditch the long underwear top for the same reasons.

On the PCT, I never hiked in anything other than my base layer, Houdini, and rain jacket. I had one extra t-shirt for town/sleeping and an insulated jacket. For the Sierras, I added a mid-weight poly shirt for sleeping, but I had a pretty light sleeping bag and needed the extra warmth. If your sleeping bag is rated to 20 or lower, you probably won't need a lot of warm clothes to sleep in.

I have convertible pants, but I've only removed the bottoms one time on the trail for a creek crossing. It took so long that I never did it again.

I prefer boxer briefs with a 9" inseam because I find that shorter briefs ride up. UnderArmour, Starter and Champion make decent 9" inseam boxer briefs.

Is the long underwear for sleeping? If not, I imagine they'll become too much of a hassle to change in and out of while hiking.

A rain jacket will certainly break the wind enough. The risk is the extra wear and tear might make it less water resistant.

For me, a wind shirt would be more than enough insulation while hiking, so I wouldn't carry one of those shirts. I used to carry an R1 hoodie, but found I never needed it. When I take breaks, I have a puffy jacket.

You could probably leave some stuff behind

I would suggest:
Montbell EX Light Down Jacket – 5.7 oz
OR Helium II – 6.4 oz
Patagonia Houdini – 4.3 oz
North Face Paramount Peak Convertible Pants – 2O oz
Icebreaker BodyFit 15O Apollo T-Shirt – 5 oz
Icebreaker 15O Long Underwear Top and Bottom – 16 oz
Ex-Officio Give-n-Go Boxer Brief – 2.5 oz

The thick wool shirt, and extra T-shirt and undies are redundant.

Hike in T shirt. If it's windy or drizzly, wear the Houdini. If it's very rainy and cold, wear the rain jkt.
In camp, wash T-shirt and undies, wear long underwear top and bottom, add down jacket, Houidini, Rain jacket as needed.

You could swap the long underpants for briefs in the warmer stretches.

The thick wool shirt, and extra T-shirt and undies are redundant.

No sunvisor/hat? No beanie? No sunglasses? No socks?

Those are some heavy pants. Do you really love the zip-off? I find a pair of shorts (5 0z)plus a pull on Dynamo windpant (3 Oz) easier on off than the zipp-off legs. Plus you have something to wear in the laundromat or at night if your pants/shorts got wet.

You could swap the long underpants for briefs in the warmer stretches.