Hi and welcome, AmberLeaf. If you could tell us where you are, it will help us to advise you better. Please fill in your profile with your city/state/country - it's the little person icon in the upper left blue sidebar.
Citrus have a very specific fertilizer blend, so you would need to buy that for your citrus trees. But that fertilizer should also be fine for your other plants as well.
I don't think there's enough compost around for you to use it exclusively, especially if you are in the deep South (as it sounds like you are) where we get heavy rains for months in the summer. It leaches nutrients out of the soil very quickly when you get a couple of inches of rain per hour. Bananas specifically are very heavy feeders and can benefit from generous, consistent nutrient supply. They also need a ton of water which leaches the nutrients even when it's not pouring rain.
As far as the "kind" of compost, just about any compost you can get in large quantities will be fine - the more the better. As long as it's fully composted, it's reduced to basic plant fibers no matter what it was to begin with.
