But I can't leave it at that, right ;)
Add two small plastic bags, loaf of bread size, almost weightless, and here is why:
This year there will be lots of walking through water: river crossings, creeks, flooded trails, just tons of water everywhere. You have no water crossing shoes listed so I assume you are just going to plow through it all with your trail runners - good plan. In the evening you'll take off those wet shoes, wash out your muddy socks, dry off your feet with your buff, put on your clean dry sleep socks and be happy. Now when you inevitably need to put your shoes back on to take a walk around camp you will not want to put those SLOPPY WET shoes back on! So you put your dry sock clad feet into the plastic bags before you slip into those shoes and you'll be fine and your socks will stay dry.
Personally I'd bring a third pair of socks as well, two pairs to wear hiking (one pair drying on my pack, one pair on my feet, and the third pair reserved for sleeping), but hey that's just me.
Bring a real compass!
Your zero point something ounce compass doesn't count. Bring something you can navigate with! The JMT is very well marked and you probably will never use it. BUT this is an exceptionally high snow year, you could loose the trail and then you need a real compass and a map and the knowledge to use them to get back on track.