What's your proposed start date? That makes a huge difference on what you need to carry.
- Sleeping pad?
- I would cut your hydration system back to 2 liters. Water's heavy! You can easily use just 2 liters, or less, on the AT.
- The Colombia Buggaboo is way too big of a rain jacket! Find something lighter and packs down easier.
- How heavy of a fleece are you taking? Same question on long johns.
- Insulated rain pants? Too heavy. Standard rain pants work fine.
- Lighters/matches. One lighter.....maybe a backup but not both. If yours fails, borrow someone elses.
- Flask? What are you carrying it in?
- mini mag light. You've got a headlamp. Don't need both.
- What kind of first aid kit? Don't need a huge one....just some basics.
Good basic list. You can still cut some things.