Great list, great trip ahead of you. Loved the JMT, and just looking back at the JMT photo thread last night, I want to go again very very very very very bad.
First thing that caught my eye was the SPOT, haha. My parents said the same thing about my trip. By the weight you posted, it looks like you have the SPOT 2.0 or whatever it's called, good for you.
I've used a steripen and filter before, and it works well. Perhaps also consider Tony Wong's gravity filter set up, which weighs about half of what you're doing now, and requires no effort. Though of course it has drawbacks, such as maybe getting another water container to fit your preferences, it can be done quickly and with little effort, and even as you walk (filter thru the bladder as you drink).
I also see a platy as well as a camelbak... confused. Explain? Do you need two bladders? I imagine you won't need more than 3 liters at any time, maybe 4 but that would certainly hold you over all day. You could maybe carry one less container and just refill during a lunch time?
Trowel for poopin? My advice, take it or leave it: be a man, use a stone or stick to dig your hole. I guess it should read, be a caveman. Many an ounce saved.
That's a great stove you got, the regulator! Good choice! I don't know how much you'll need to have a regulated stove, but that's a great stove! I see canister is your choice, worked well for me and works for many folks. Yeah yeah yeah, you could be lighter if.... but you know that.
Looks like a great list! But a camera and a journal to remember it by? I love opening up my JMT journal every few months. It brings back memories I've otherwise forgotten. I regret the couple of nights I didn't write anything, too. Worth its weight in gold, in my opinion.
I used the same bag on my trip (WM) and was plenty warm, but I'm sure you're a sierra junkie as well and know this. You're gonna have a great trip.