I would only put a pair of angels in a 30, but maybe that's just me...
beyond that, Bolivian Rams (Microgeophagus altispinosa) is a very nice fish and you could have a pair of them and maybe a pair of German Blue Rams (Microgeophagus ramirezi) -- but both of those species are territorial during breeding, so it depends on the footprint of your tank.
I would *NOT* add N. leleupi to your tank (lemon cichlids), these are african cichlids and have special requirements which will make your other fish unhappy, or vice versa.
I also agree that barbs are a bad idea with angels, the angel just isnt fast enough...
This is something of a controvercial topic, but you may also want to try Neons if you introduce them when the angels are relatively small. Neons are an angel fish's natural food, so watch them carefully. They do fine in my tank with a 4.5" Angel. I tried cardinals first (they are bigger, so less likely to become lunch) but they are much less hardy and get stressed easily. If you go this route, I would get 6+
You might go with some algae eaters, like a bristlenose pleco, an SAE or two and a couple Ottos. (but make sure you have algae or suppliment their diet or the pleco and ottos may starve to death...SAEs will eat flakes, brine shrimp, whatever)
Cheers!