Ok I use to have a 75g African cichlid tank and absolutely loved it. The stocking question really depends on do you want to have breeding or want a flashy looking tank? My 75g was an all male tank where you didn't have the aggression as much because there were no females to fight over and their coloring was beautiful. Have any cichlids caught your attention? If so, what?
The 700gph for the filters is very good, I had 750gph but you are definitely in the right direction for that. What you would have to worry about with plants is the cichlids may uproot them or eat them. They would most likely put the plants where they think they should go, but I do know some people have had good experiences with live plants and cichlids. I never tried live plants with my cichlids.