My initial thoughts are that you are going to be wearing too many clothes while hiking in all but the absolute worst conditions. I am fine hiking at cold temps in a lightweight wool baselayer top, windshirt, nylon pants, 100wt fleece hat, 200wt fleece gloves. Remember if you aren’t cool starting out in the morning, you will quickly overheat.
You shouldn’t need the balaclava while hiking, but it will be a welcome addition to you r in camp wear.
Again, I think you are wearing too much while hiking. I would probably wear one baselyaer and keep the other one for sleeping and in camp use while your “hiking” one dries. The fleece will help supplement your down jacket in camp.
I also think you will probably flip your gloves, hiking in the OR Flurry Gloves adding your waterproof shell gloves when needed, and save the liners and insulated mitts for camp. I like to take extra liners in the winter and rotate them to keep them dry.
Unless it is really cold, you won’t need to hike in the long underwear bottoms. You might use them at camp for warmth and to keep your body oils off your WM pants.
I would go with trail runners instead of boots. I have used my trail runners in a foot of snow with waist high drifts with no problems, and there probably won’t be much if any snow up there anyways. (might have none, but could have 2 feet of it) If you expect snow, Gore Tex socks might be of help in your trail runners.
You definitely need to supplement your Neo-Air with a CC Foam pad. I would probably look at a Ridgerest, or at the least a GG 3/8” Thinlight.
Get rid of the 10oz pillow and just use a stuffsack filled with clothes/raingear/etc. You can also put a platy full of water under it (also keeps it from freezing most of the time) and your shoes under it (same thing – keep them from freezing)
I know you might use your Jam, but that Bora is awfully heavy. The jam might end up being too small though.
I would drop the pack cover and replace with a Trash Compactor Bag liner. They work better than pack covers in the rain.
What kind of stove are you using? Alcohol? I have used Alcohol in the cold but they are not as easy to use nor as efficient in real low temps. Just be sure you know the limitations of the system before you use it.
If you are staying on the AT in the park, you can’t use a tent anyways so I wouldn’t carry such a heavy one. I might take a tarp or bivy to use in an emergency, but not a tent.
Even if you are not staying on the AT, drop the groundsheet, tent floors are durable enough without them.
Water is very plentiful; you will not need to carry three liters. You could get by with one liter if you wanted, but two gives you plenty of cushion.
Drop the GPS, you will not need it in the park.
That knife is a little overkill don’t you think? You could get a small Swiss Army Knife, Gerber Mini LST, or Spyderco Ladybug for 0.6 ounces.
You shouldn’t need extra batteries for a 2.5 day trip.