To answer your question and give credence to Steve's...
1. Staking...It's rocky but most of the campsites will allow for staking.
2. Fleece/Down...I use down exclusively in the Sierra summer but it is an 11 oz. down jacket, which is warm as Polartec 300. Temperatures can be mild to cold any time in the Sierra. One of my coldest Sierra nights was in August...and I'm a four season backpacker. Just check the forecast and Cottonwood Lake Reporting Station prior to putting your clothing list together for this trip.
3. Stove...Canister is fine. If it's very cold, sleep with the canister or put in water when you fire it up. Both will improve performance.
4. Parking...is hit or miss. If nothing is available, drop your gear and find the best possible spot. We usually park in the overflow area for our trips.
