You really don't need that many layers. I carried the clothing that I hiked in the entire time for sun protection and then I carried a couple of layers for resting or bad weather.
I hiked in convertible pants for sun and leg protection. I rarely converted then to shorts, but the zippers were nice for venting.
I hiked in a long sleeve button down shirt from Mountain Hardware that was designed for desert travel. I rolled up the sleeves when I got too hot.
Also carried: sun gloves, light wool hat, rain jacket, windshirt, extra socks, light down jacket, fleece mittens (used in so cal just as much as the sierra!), sun hat, base layer top. I don't think I carried base layer pants. I also picked up a cheap pair running shorts just to wear while doing laundry.
On the first day you will climb from a small creek bed up a decent sized hill before you reach Lake Morena. You will probably reach it when the day is hottest. I saw a small pile of junk that someone ditched. Included was an extra pair of shorts and a short sleeve shirt. Think really hard if you want to carry a change of clothes for 2000+ miles.