On Air vs Static,
Airbags only replace the springs in the truck, so whatever you go with now will be the same minus the springs (in the front) you still need spindles to get a low ride height and just change the install height of the bags to match later on.
What are you plans on the rear? Are you going to do air over leaf or a 4link or what? If you go 4link in the rear with coil-overs when you bag it, you just basically replace those. If you go air over leaf, you just remove more leafs (down to 2) and put a bag on top.
I would weigh the cost of both before you decide as you are still going to have to lower the truck when you bag it. Airbags just add adjustability and the ability to let all the air out when parked.