It depends on how quickly you think you need to access them and what kinds of guns they are. If it's an antique with a delicate blued finish I'd protect that differently than I would protect a Glock.
Steel components need to be oiled, but don't bother if it's too hard to get to (like a mag spring or something).
I recommend Ballistol because you'll want to lay it on pretty thick. It will work as a lubricant, is non-toxic, and doesn't hurt leather and wood.
There is only one place that really, truly matters: the chamber. Brush your chambers, put patches over the brush to scrub them clean, and then oil them. Remove the oil with patches before shooting however. If the outside of your slide gets pitted, it won't really matter. But if you have a pitted chamber that could easily lead to failures to extract.
Long term ammo needs to go in a quality ammo can with a dessicant inside. Do not put any oil or solvents on the ammo, leave the ammo in the factory boxes, and don't handle loose rounds unless wearing a glove.