Cichlid aggression and Stocking help

[duanes]

The new cichlids you chose are Central American, and as far as water goes they prefer and come from the same type hard water as the Africans do.
They use lip locking as communication in assessing dominance (in lieu of actual physically damaging fighting if possible) if the tank is large enough, and in displays of courtship.
Catfish share natural waters with cichlids in many areas, but are also enemies preying on each others fry, so some instinctual aggression should be expected.
Where mbuna live in Africa, there are catfish that lay their eggs in the same spot cichlids do, and the cichlids will incubate the catfish eggs, the catfish fry eat the baby cichlids inside the cichlid mothers mouth.
I agree with Gourami Swami, other African mbuna would be a better choice.
Mbuna live in colonies in nature, where they guard territories that are almost like algae farms which they tend, and eat along with the micro animals that live in the algae.

 

[Gourami Swami]

Catfish can do fine with cichlids, they live together in the wild as Duanes said, in both Africa and central America. Not quite sure what kind of cat that is, some get huge and would eventually eat the cichlids. At a small size cichlids could attack the catfish, but cats usually are pretty good at taking the abuse.
If the cat gets larger than 12", I would say it needs a larger home than a 75 and would probably snack on the cichlids. If it stays small it should be fine.