Angels are cichlids and can be kept in community tanks. They are peaceful and do really well with cats, loaches, tetras, anabantiods, and most oddballs.
Cichilids need lots of veggies in their diet. They also take meaty foods, but veggies will bring out their color. Mine take live plants and algae wafers. They will take anything and can live off of anything. Most people feed their Oscars feeders, but an Oscar raised on plant foods will do just as well.
Africans and most South Americans need to be left with fish that hide or don't move a lot. They will dirty up their water, uproot all kinds of plants, and routinely pick out and kill weaken tankmates. Some even form 'alliances' and all are very territorial. Big cichlids can be sluggish though, so a really fast fish might do okay.
Cichlids, while filthy and mean, are very entertaining. They 'shudder', back up to the Penguin for fresh water, and 'goose' each other endlessly. Mine also sleep at night with folded-up fins in a huddle on the bottom of the tank. Be warned; cichilids breed like rabits.
Best of luck!
lashilia