If ya get the trets, you'll wanna get several to ensure aggression is diffused. They get 6" and fairly nasty for lamprologines. They're not blue, but if yer lookin' for stripes, ya may check out Neolamprologus cylindricus. Smaller and not quite so temperamental IME.
Be careful with the brichardi, as well. If they start breeding they can take over a tank fairly quick. The main breeding pair will allow juveniles from previous broods to stick around and help raise fry from subsequent spawns. The combo of one adult pair and several near adult juvies can be overwhelming to more timid species. Ya might also look at caudopunks, Neolamprologus caudopunctatus, for a plain bodied fish.
Callochromis are open sand fish and occies are shell-dwellers. By the time ya add shells for the occies, yer takin' up open real estate for the callochromis. So if ya opt for either of those, I'd suggest one or the other and not both together.
WYite