I think that you need to do some additional research before mixing some of the fish that you currently own. I have seen pretty much everything possible when it comes to mixing African cichlids, but in some instances certain species are IMO best left out of the mix. As an example, Frontosa do best in groups of their own, not in a tank with territorial fin nipping mbuna. Ditto to most parrots, in many cases due to their mouth shape & bite they won't be able to properly defend themselves, especially against much faster fish. Typically they are not a good fit.
Also, no matter how much filtration you have, the higher the bio-load, the greater the volume & frequency of water changes required. More fish = more maintenance.