Those dots are called egg spots its a sense of lure with a female to try and grab those egg spots so that the male will be able to fertilize the eggs in her mouth.
As for plants go, i would stick with the self attaching plants like anubias, java ferns, java moss and maybe some vals, try to structure some rocks around the plants to keep the cichlids from digging or removing them from their intended spot.
Most species can interbreed, its more common when you have mouthbrooders together in the same tank.
As for sexing cichlids the most accurate way of sexing is called venting by looking at the areas where fish would normally expel bowl movements, google venting cichlids or sexing cichlids you will get a wealth of information on how to sex a cichlid, those egg spots could be females as well.