fairy lamps, are fairy lamprologus, another name for brichardi, it is not good to mix continents for many reasons, main ones being opposite water parameters, south americans like soft acidic water where as rift lake cichlids like hard alkaline water, also south americans get larger and more agressive then most african rift lake cichlids, new worlds generally need a high protein diet where mbunas tropheus and goby cichlids need a diet of mainly algae, i wouldnt mix anything with the brichardi, id say keep them alone in the tank they will do better in a species only tank, hm min tank size id say 29-30 gal, i use a mix of 1 tble spn instant ocean, 1 tspn baking soda, 1 tsp epsom salts per 5 gallons to raise gH, kH, and PH to good levels for africans, if your city water is not hard enough and has a pH under 7.8-8 you may want to think about doing it (for brichardi, for malawi cichlids can be 7.5< but lake tanganyika is harder), yes assorted africans will breed with each other, often very easily, esiest way to sex is to research the species you have and see waht the differences are in the sexes, pecking orders will usually change if something in the tank has been changed like new rocks or rocks taken out or new fish, in my experience pecking oder has not changed when a female has been holding