Yeah go for all of the above, lots of yellow looks good as for number of fish provided you have really good filtration and do regular water changes its definately recommended to overstock with africans.
We have Johanni in our tank and they can be a bit nasty, I think our male is a bit softer than most because we only have one female and shes fine shes even holding atm and not being wasted by him.
Also try and avoid fish that can cross breed given the chance (if you plan to keep any babies out of the tank). And also watch out for fish that get too nasty for your tank when grown, just do your research or buy them young so you can rehome them as soon as they start becoming a problem. I hear a rumour theres one of the best african breeders down there but have no idea how to contact him and dont even know if he sells to the public?
heres a site
http://www.cichlid-forum.com/articles/q ... e_list.php
Have a look through here (and the cookie cutter for the 55gal) to get some idea maybe the profiles and forum on there is of some help to you..
Good luck!