Keyholes but i like shell dwellers too which are from South Africa..Anyways, Doodles, what SA cichlids were you thinking about?
Personally i would leave the tank to cycle and not get a pleco, the brown algae will disappear once you start doing water changes. I would also set up a lower ph tank for plecos, doesn't even have to be that big but they are fascinating catfish, well worth the time and effort in their own right and not as a tool.