Hi Brittany,
I can't speak to any of the AT besides the Whites, but you might want to check out Ben & Lauren's blog at http://bltadventure.blogspot.com/. They were '07 NOBOs and had a gear list that was very similar to yours. FWIW, they carried GoLite umbrellas and Dri-Ducks jackets. If you got a similar garment, it could double as a windshirt, thus taking an item off your list (you could omit the umbrella then, too). I carry a silnylon poncho, windshirt and brimmed hat, myself, and hike in wind pants 'cause I'm a klutz.
Your headlamp could be lighter; have you looked at the Petzl e+lite or a Photon Freedom with a hat clip, each of which is well under an ounce? That also sounds like a lot of DEET to start out with. I know the following will add weight, but have you thought about: camera, sunscreen or visor/hat, earplugs in case you're stuck in a shelter or hostel with snorers? Oh yeah: and a little soap, like Dr. Bronner's, and some alcohol gel (Purell).
Ok, enough from me. Time for some thru-hikers to weigh in. Have fun!!