basically as kopix said, some people say if you grow the fish up with neons they should be fine, personally I wouldnt, if you want the neon look go for cardinals. Any tetra (or similar) that grows at least to cardinal size should be safe. Swordtail, mollies and plaites would be fine but I've seen angels go for guppies so in my experience I'd say no. Most of the smaller catfish (or plecos for a larger tank) should be good, dwarf cichlids should also be fine along with most of the smaller to mid size New World Cichlids
Anyproblem here would come at breeding, but in a large enough tank it shouldnt be to much of a problem
Andrew