Welcome to Fish Lore Raine

I can see you've done your research/reading regarding your tank already, which is excellent.
I agree with Chief Waterchanger on the stocking of your 22 gallon tank. While you technically could have 1 Angelfish in a 22 gallon 20" high tank ... I think this tank is still too small for a fish like Angelfish. I personally recommend at least a 30 gallon tank for Angelfish, and 2 Angelfish at most in such a tank. Gouramis and Angelfish are not exactly compatible tankmates as they can both get territorial. I know from personal experience that Angels can get aggressive towards other fish (and even towards their own kind) especially during breeding times. Considering your tank size, I think it would be much better if you got yourself a beautiful pair of Dwarf Gouramis (preferably male and female). A few Otos would be fine in your tank too, as long as it's not overstocked. But since you want only Dwarf Gouramis, it won't be overstocked and you'll have plenty of space for a few Otos.
You certainly can have driftwood and live plants in your tank too. That would be great and it would look beautiful. If you're interested in a low-light planted tank, you should definitely read this:
http://www.fishlore.com/Forum/index.php?topic=12673.0. You can buy aquarium-safe driftwood at any fish store. Just remember to soak and boil it well before you put it inside your tank. Otherwise, it will leach tannins and stain your water orange/yellow color as well as it will bring your pH down a lot.
You don't need to wait months between adding each fish to your tank. A few weeks apart is OK. Of course, provided that the tank is cycled first

But I'm sure you already know that.