SIBBG approved Canisters are mandatory over the majority of the JMT and all over Yosemite. Go here
and scroll down to click on the map of canister required regions in the Sierras. I know someone who was escorted out of the wilderness when he was caught hanging food instead of using a can.
Spinnaker is lighter but noisier than silnylon.
The Arc AT is only rated for 40 degrees - you will FREEZE without more insulation than that. I would suggest a 25F rated quilt at minimum in the high Sierra, in summertime. For a couple more ounces than the Specialist you could have a JRB 3 season quilt for less money - mine has taken me below freezing and been consistently warm, and I am a cold sleeper.