Might work with central americans, as many CA cichlids also like hard water with a higher pH around 8. I believe the mdoko are omnivores, so a balanced cichlid diet like NLS would be appropriate. The issue I could see coming up would be aggression from the central americans, as the placidochromis are not usually very aggressive. If a large central decided to lip-lock, the placidochromis wouldn't know what to do, might even get their lips ripped off. Personally, would just keep the placidochromis with other haplochromines. But with the right centrals, maybe rainbow cichlids for example, it would probably be do-able.