Under certain circumstances, you could have a nice school of cories and a large shoal of a tetra that doesn't nip long fins. I really don't think you are overstocked at all. It's like a 47g tank right? I keep my angels with Cherry barbs, which are not much bigger than neons. The angelfish were, however, introduced afterwards and were very small when I got them. Careful, though, with cories and the rams if they decide to breed. You may want to opt for a larger cory species or make sure that they are in larger numbers. I keep Brochis splendens and Corydoras pulcher with my breeding angelfish pair. Both species get to be about 3 inches or more and are more than able to handle a large angelfish without eating smaller species. Really nice showcase catfish. You could opt for like 10-12 of the catfish and 12-15 of the tetras, or simply increase the numbers of your barbs, which is always a great option. A really nice shoal of barbs is very attractive to look at. All this stocking advice really depends on your maintenance regimen. I'm pretty diligent (weekly water changes), have a very strong HOB filter, and have planted the tank, so I can stock my tanks heavier than normal and have fish that thrive. If you don't follow this regimen, which is entirely up to you, I'd opt then to get shoal of cories, about 8, and then just increase your Pentazona shoal to 10. You'll get better movement from the Pentazonas.
I'm impressed, though, your angels don't eat shrimp? I wouldn't risk that with my angels, they are little piggy poos.
