to keep them well you need a 200L tank or larger IMO. also the key to keeping africans is to set up well, as above plenty of hiding places is a must. Aim for at least 6 times the tank volume of filtration per hour (200L tank aim for at least 1200lph canister filtration) and feed plenty of good food like NLS cichlid formula, JBL Novorift and Sera Granugreen and granured.
A good sized group, say 6 or more yellows will readily breed with the right ratio of male to female and adding the blues or dems has been done plenty of times with good success.