This list is a good start, in my opinion. Like everyone, there are a few things I would tweak. First off, I think your pack is fine. Yeah, there are lighter packs, but the worst thing is to load your gear, food and a bear canister in a pack that doesn't muster the load well. I can't speak to the merits of the Go Lite Jam 2, but I can say that I haven't had much luck with a lot of the suspension/belt combos of UL packs. But perhaps I need to pack much lighter! (Which is probably true). I guess if I had to make choices, I would start with other gear before the pack, especially if you are used to the pack and like it.
I assume you are going to stay with your sleep system, which is fine, since you are invested in it.
As others have pointed out, you will need a bear canister for the Sierra. You can use bear boxes, but they are few and far between and restrict where you can camp.
There are lighter headlamps out there, and you might be tempted to replace your lamp for a lighter model. I have voiced this refrain a number of times, so excuse me if you've heard this all before, but I will almost guarantee that you will need to hike at night at some point on the trail - whether that be in the SoCal to avoid the heat of the day or because you are racing to make it to a post office before it closes for the weekend. Night hiking is much tougher with a tiny headlamp that doesn't throw much of a beam. It can be done, of course, but speed will be greatly reduced. I carried an ultralight headlamp but at the point I became a danger to myself hiking with it, I resigned it to camp use only. Consider the beam and brightness.
You might consider wearing pants in Southern California unless you plan to carry a great deal of sunscreen. I found that the pants helped prevent sunburn and resisted the brushy overgrowth. Everyone is different in this respect, but I was glad to have pants for the trip. Others hiked exclusively in shorts. YMMV.
On your warm weather gear, it can get cold in the mountains everywhere, I echo Nia's sentiments on carefully choosing the right gear for the situation. You can switch out the fleece, which will not compress especially well, for a MontBell down jacket that is at least 4 ounces lighter, compresses down to nothing and is every bit as warm or warmer.
I also agree with Nia's assessment of the blue foam pad. I also had better luck with the OPSAK than he did. I did have mine line a ultralight food sack, which maybe helped.
Agree on dropping a number of stuff sacks - you can make do without.
Finally, you will have a touch under 3.4 liters of water capacity. This is pushing it, in my estimation. There are a few relatively long (15+ miles) stretches with little water. When it is hot, this can become a pretty big concern. Plus, it can be very dry, so dehydration is an issue. I carried four - and if it was really hot - five liters these stretches. It wasn't particularly fun, but necessary.
Have a great journey!