I'd actually avoid smaller dwarves in a larger tank. I've had no luck with keeping any a pistons in my 75 with my new world cichlid community. I do have a young mikrogeophgus ramirezi that is doing well.
For a 150, I'd recommend doing some of the larger South American cichlids, like Uaru amphianthancoides or hypselecara temporalis. Them have a small group of eartheater cichlids, like geophagus altifrons, tapajo, tapajo II, pindare, etc. then doing some smaller accent cichlids like cleithracara maronii, aquidens pulcher, krobia xinguensis, gymnogeophagus meridionalis. And then finally do a couple large school of cories, like Sterbai and agassizi, as well as a couple schools of tetra species, like lemons, bleeding heart, cardinal, black neon, rummy nose, diamond, etc. then, also adding a couple larger catfish species like hoplo cats or porthole cats.
I have a similar mix in my 75 and have had some success. I would save the dwarves for smaller tanks, as they seem to get lost in big tanks unless the entire tank is void of larger fish