When asking questions for advice, you need to give as much information as possible about your setup. What if someone suggests a school of tinfoil barbs but you have a 30 or 55 gallon tank? That wouldn't be good.
What size tank do you have and what kind of cichlids are you talking about? i.e-large Central Americans? Africans? Discus? Peacock Bass? Bolivian Rams? Eartheaters? Other?
hmmm, that red devil will eventually take over the tank entirely. If you opted to remove it, then I would suggest giant danios, silver dollars, or maybe (and this is a big maybe) even congo tetras
Yeah, like Onion said, the Red Devil is going to eventually give the other fish hell. If your cats have caves then they should be ok. I don't think dithers will work, and the JDs will get killed.