I last hiked the JMT in 04. Hiked from Lake Tahoe to Tuolumne Meadows (~185M) last month. Some other Sierra hiking in between.
Couple of observations: I've never been a hammock camper. I think I'd rather not try finding trees along the JMT (often above timberline) to set up shelter. I'd stick w/ a lightweight tent or tarp situation. I'd see if I could whittle down some weight in some areas and add a little in my sleeping pad. I used a Z-rest (72") in 04. I now use a Neo Air (basically the same weight - ~14 oz - w/ greater comfort. My old bones probably wouldn't like the 7 oz GG pad. I don't understand the knife & multitool. I'd pick one and leave the other. I'd probably swap one of the 1L Platypus for a 2L. The GSI Minimalist is really pretty heavy for it's size. I weighed the full kit @ 6.4 oz. I'd use a .9L Evernew pot (my solo go-to pot) or something smaller/lighter. A phone would probably be useless as a phone. Not sure of the quality of the photos from an I-Phone. You could shave an oz or so on your headlamp, towel, pillow/stuff sack, etc. Your maps will probably weight more than an oz. I used Tom Harrison's map set. You could print the PCT map set of that section (covers most of the JMT; missing the start & where the JMT & PCT diverts after Donohue Pass) from PCTMaps.net. You'll need to add a bear canister. Make sure your pack works with it. Some of the smaller, frameless packs can be tricky w/ a canister.
What I'd do logistically if I did it again: Plan the miles per day you want to hike. If you do 12M/day, the hike would take 18 days. Adjust up or down from there. Maybe add a layover day somewhere at a resupply point. I'd resupply every chance I got. The following examples are for 12m/day itinerary - Tuolumne Meadows (day 2, maybe 3 if you want a side-hike of Half Dome), Red's Meadows (day 5), & Muir Trail Ranch (day 9). Vermillion Valley Resort is two days after Red's and a day & a half before MTR. If you want to stop there for an additional resupply and clean up (showers & washing clothes), I'd camp at Mono Creek 2 days after leaving Red's. Catch the early boat shuttle to Vermillion (10 am?). That would give you more time to get stuff done. Take the shuttle the following morning out of Vermillion (1st night & beer was free when I was there in 04).
Injury or illness can come into play on the trail. Be aware of your bail-out points - Tuolumne Meadows, Red's, Bishop Pass, Kearsarge Pass, etc have access to Hwy 395 to the west. I've used Bishop Pass (buddy's injury) & Kearsarge Pass (my injury) on previous hikes. No hitching problems at either location (I must have looked like I didn't smell bad; but I did!).
Have fun on your hike.