A short trip like this is a great way to challenge yourself to go lighter! Over 13 pounds of base weight is a lot. You could easily trim it down to something a lot lower.
3 pairs of socks for two nights? Okay, fair enough.
NIX the sleeping bag stuff sack and the clothing dry bag. Trust your one COMPACTOR bag!
NIX the tent and just take a tarp. This will save a LOT of weight.
NIX the 12 oz filter (uuugh!) and just take aqua-mira drops. (avoid the tabs, they take too long to work, the drops are quicker and you can monitor how much you use depending on the perceived quality of the source - and they make the water taste like chlorine)
WHy 3 liters water capacity on mountain route? This seems overkill unless you were in the Mojave with ZERO water sources.
NIX the TP and Trowel.
NIX both knives and take a 0.01 oz single edge razor blade (the lightest!)
NIX the extra camera batteries and just start with a fresh set.
I can't imagine it's buggy in the Sierras in september. NIX the bug stuff.
Eat out of your pot, and NIX the mug with lid & cozy (but make a cozy for your pot)
I like the AGG 3 cup pot, it is a nice size and as light as titanium!
You say you are still going to add WALLET and PHONE. You'll be fine without these! Leave 'em behind.
A 32 ounce pack? Uuugh! There are plenty of lighter options.
You are taking 10.7 ounce pants AND hiking pants? Just take the hiking pants (which I assume are quick dry nylon) and NOT the rain pants you've listed. If you do add RAIN pants (like the Dri-Ducks) then NIX the long undies. For two nights, you'll be totally fine.
The Dri Ducks pants are easily torn, but they are ridiculously light if you were to use 'em as an extra layer over everything as a way to stay warm in early mornings.They are VERY breathable too. But, treat them carefully, they rip easy. They mend great with simple masking tape! And - If you get Dri-Duck pants, use the excellent parka and nix your 10.4 oz rain coat.
Use your 3 cup pot to dip for water (because you are leaving your mug behind, right?) and this will make filling a platypus easy.
If you are worried about floaties (and is that *really* a problem in the mountains? I've NEVER had any issues with water in an alpine environment - only in muddy desert pools) take a 1/2 oz plastic kitchen funnel, and set a piece of fabric in the cone when pouring the water thru.