First off, congratulations on diving into this hobby! It sounds like you've gotten a little ahead of yourself, and there's nothing wrong with that! I agree with Brewcrew86, go ahead and rack into the keg with your priming sugar. Oxidation won't be a problem... this is rarely an issue in homebrewing -- it's more of a concern for commercially distributed bottled beer. Anyway, if your kegs are like mine, you will likely get a good seal without adding pressure. Just take care to keep the lid nice and centered as you latch it down. I like to pull up on the lid as I clamp it, to hold pressure on the gasket as the latch clamps down.
The worst thing that could happen is that you don't get a good carbonation because of a small leak. No big deal, just force carbonate once you get your CO2 rig.