The stocking in post #3 will not work in a 55g tank.
First, when dealing with neotropical cichlids (this means cichlid species that occur in the tropics of the New World, i.e., South and Central America) different species of cichlids should not be combined unless the tank is very large and then depending upon the species involved. Also, gourami should not be combined with cichlids.
On the angelfish, a group must be minimum five, not two, three or four. Angelfish are shoaling fish but they develop as hierarchy within the group, and you need at least five to ensure aggressive behaviours are spread around. Also, all five (or more) must be added together at the same time. The hierarchy can form quickly and new comers are usually seen as unwanted intruders and in an aquarium which by its size provides no significant space for the fish to get out of each others' sight, this is usually disastrous.
The Raphael Catfish gets large, six inches up to eight inches, and it will readily eat any small fish. They have a very large mouth opening. Also, this is a nocturnal species, and this can make sedate fish like cichlids very nervous and stressed, which means poor health and more disease issues.