I second what FreshwaterPredator has said. Mixing africans can be done, but i personally wouldn't do it. But thats just my preference. If you are purchasing your fish from a large petstore or an lfs then it is likely you will be purchasing Tank Bred specimins which are adapted to all water conditions. So that issue can be overcome. However, if you are looking to pirchase f# i would look into it some more.
As for pairs i would leave them out. As with any cichlid they get very aggressive around breeding time (even the more timid ones such as severums) and the last thing you want is a fish with tatty fins or deaths within the tank (which can happen if you have lots of fish in with breeding pairs). Also, it is unlikely that a good portion of the fry will survive with other fish in there. Which will cause both you and yourfish to feel bad. Granted you could pull the fry - but to me that defeats the purpose of having a pair.
Just a suggestion, if you are looking to exhibit some breeding behaviour in cichlids especially (i find this half the appeal of cichlids). Then you may want to look into a biotope? With the focus on a pair of cichlids? I am currently in the midst of my 135g peruvian biotope, in which a pair of white saums will be the focus. And if all goes to plan, these fish display some crazy colour. Just a thought.
Also, i didn't see any mention if the following SA/CA's? These might be worth looking into, vs. the africans?
Gold Saums, Thorichthys species - such as the firemouth (meeki) and ellioti, honduran red points (hrp's), Blue acara's (wouldn't mix with the gold saums- one or the other).
Those are just a few of the smaller-ish ones. Meaning you can have a larger stocklist, which nearly everyone wants! Go onto google and type in CA/SA fish profiles - there is so many different species that i don't think you'll want any africans.
Finally, don't go with what i or anyone else says. Go for what you like as no matter what you have someone will always disagree. Good luck!