Unfortunately, it won't be suitable for this mix of fish IMO. I'm with Jpap on this one... it's better for the fish if you choose to do either an African setup or a SA/CA setup. If you want more options for fish in a 75, I'd lean toward an African setup... many SA/CA cichlids (like the green terror for example) need a 75 as a bare minimum due to their adult size. With an African cichlid tank, you could keep a nice variety of fish in a 75, and have a ton of color and activity. Unlike SA/CA cichlids, you can often get away with stocking an African tank heavily, as it disperses aggression (at least for mbunas).