Not sure about brakes, to be honest brakes are the least of my worries. If you're serious about it, then upgrade to drilled and slotted rotors and organic pads (won't heat up as quickly).
The fact is, 8k is too much for a single cab short bed. Weight distribution won't do crap. The wheelbase is too short. You'll never be able to handle that amount of weight behind that truck. It'll throw you all over the road. There's a reason 2500/3500's don't come in single cab short bed configurations. They would be too unstable while towing.
Air bags, weight distribution hitch, trailer brake controller...it's all for nothing. The truck will not be physically capable of handling it.
IF you're dead serious about using the truck to haul with, and choose to avoid our advice on parting ways and investing into a proper truck to haul with, then here's the advice I'll give to at least TRY to keep you safe.
Invest in some 3/4 ton rear springs or have someone build you a set of springs.
Install a rear sway bar, and upgrade the front sway bar to something heavy duty.
Invest in the said brakes I listed above.
Invest into the air bags you mentioned, do some Firestone Ride Rights or something rated for the 5k leveling capacity.
Invest in some 10 ply tires.
Invest in some rear shocks (like Rancho 9000's that are adjustable)
Make sure the truck has a hitch rated for that kind of load.
Do a once over on the truck, make sure there's no frame rot or anything of the like to prevent the truck from folding in half if you have to stomp hard on the brakes (sounds crazy and laugh, but I've seen it happen).
Best advice I can give from here is...stay OFF the highways and interstates. Keep it under 40 mph.