Hi there,
You may encounter a bit of aggression if either pair decides to breed, but then that would happen with just about any cichlid species. Given that the rams are dwarves and the keyholes will get a little bit bigger (but still towards the dwarf end of the scale) I would think a tank with at least a 36"x12" footprint and well aquascaped would house these 2 pairs quite happily.
As to the other fish you mention, how many of each are you talking about???
Andrew