-Ditch the pack cover and stick with the pack liner. My pack would still get wet when I used one. I have seen wind suck them off of a pack before as well.
-Ditch the gatorade bottle and go with a good old nalgene that can take repeated doses of boiling water which is good for weather where hot tea and toasty water bottles in the foot of your bag is a must.
-Consider an MSR Simmer Lite white gas stove with a titanium fuel bottle. These thing will be invaluable in cold weather. Good for heating a lot of cold, cold water very quickly which will be necessary.
-Make sure your mitts are waterproof.
-Forget gaiters you have overboots.
-The seal skinz seem kind of redundant considering the N.E.O.S. overboots. I agree with the overboots but suggest ditching the seal skinz.
-I might also consider down booties.
-Keep the stays in the pack.
-A light cup may be a good thing for collecting water.
-Ditch one of the candles and keep the other candle,lighter,and matches.
-Handwarmers are a great emergency item.
-I would ditch the heavy weight tights.
-Consider a lightweight and highly breathable bivy made of pertex or epic or something for use in shelters for wind protection and use in tent for extra protection from condensation which is poopy for down bags.
-Ditch the cap and swap it for an ear warmer band type thingy.
-Keep the stuff sack for extra clothes. I repeat keep it.
-You may want to consider carrying maps which are not necessary as the trail is well marked but sure as shoot could save your hide during an early starting Nobo hike. They can help you if you need to bail out or with planning an alternate route in some necessary instances. I would at least consider carrying maps for the months of January through March.
-Also I sectioned up a Wingfoot guidebook and found it to be invaluable during my thru.
I finished a Sobo on Dec 31st before and you are sure to encounter conditions similiar to those I encountered and probably some that will beat what I saw. Your list is extremely well thought out. I hope my thoughts may be of some help. Keep in mind you are best aware of your needs and abilities when selecting your rig. On the flip soliciting advice is also a good thing to do.
Best Wishes, -jeff aka frankenfeet