Generally I don't recommend keeping more than one species of apistogramma to a tank. It can be done, but you have to be careful not to mix species that are closely related, as they may hybridize.
In a 30 gallon I would do something like this....
1- trio Apistogramma sp. your choice.
1- pair of rams
1- pair of laetacara
12- small tetras (ember, phantoms, cardinals, or any other you like)
1- bushynose pleco or 6 oto cats
This gives 12" of floor space per species, which seems to work well. The tetras will act as dithers for the shy dwarves. This will give you a nicely balanced look to your tank.
Use driftwood, rocks and plants to create lots of territorial boundaries. Keep the pH between 6&7 and fairly soft and your fish will show great colors and live happy lives.
A temp of 76-78 will suit these fish well, unless you go with blue rams or one of the color variants, then raise the temp to 80-82.