Re: dry storage
I have several guns that are wrapped in plastic bags that aren't even sealed. the guns are liberally sprayed with oil, the bag is wrapped around and stored away. I check them every couple of years and no problems. I have not had to re oil them and they are just fine. I would suggest the you vacuum seal them (which vacuum sealing them is optimum) and the wrap each one in some kind of cloth and you will be good to go.
Just make sure the barrels get swabbed out good before they get shot.