OK, my 2 cents ...

I think the people above have great advice. That pack is OK, IF it fits you well. There are plenty of external frame packs that are lighter and more comfortable - try Craig's list, garage sales, and even surplus stores. Fit is everything if you're trecking that far.

Second, a 400 mile hike. Ugh! You can't carry supplies for that far, so I'd really focus on making sure you can resupply en route. Ie, water filter (not pills), 2-3 liters of water. I know NC has plenty of water sources, but you'll still go through that in 1 day, so plan routes where you can refill water. Plan for 1 day of rest every 5-7 days of hiking - you'll need it!

Good idea w/ the 10/22 and fishing gear, for "resupply" of food. Don't forget though if you're reduced to bugging out on foot, you're going to have a LOT of company, and they're all starving too. I'd ditch the MRE's, and do either the entrees only, or add some dehydrated food or Datrex bars or something simiar. Figure nearly 2000 calories/day, maybe more, if you're carrying a 40-60lbs pack (that's for YOU only!)

FAK - adequate. I like more, but I'm biased. You'll probably be OK. Add some duct or medical tape, and some more gauze, and some more moleskin or molefoam.

How much ammo? I wouldn't take more than 3 mags of .40, or more than 100 rds of .22, but that's just me. You're eating, not fighting a war.

Knife - Mora's are cheap, light and relatively good quality. Not to mention you already have a blade on the Gerber and apparently in your pocket. So a fixed blade is almost a 'back up' too.

Tent. You've got a kid, right? You think you'll both like being wet and cold? (it's ALWAYS bad weather when you least can afford it). Make the kid carry the poles or something to help distribute the weight.

I'd ditch the mess kit if it's that old Boy Scout type (2 plates, tray, etc). Really, just something to boil water in, and something to eat with. You can eat out of the pot. Maybe a small plate to share w/ daughter. Aluminum, titanium and plastic are all lighter than stainless, which is what I assume your kit is.

Overall, good start though!