In a 7 Foot tank you may be OK to try some similarly tough CA cichlids. I have kept cichlids from the vieja family and amphilophus family with carpintis, as well as tetracanthus, istlanum, convicts, probably more than I can remember at some point. In 6 foot tanks.
Central american communities are really a balancing act. Have another tank on standby in case you need to shuffle fish around because you never know, just because I had success with something, doesn't mean it would work for someone else. Go for tough fish that get to at least 6" or larger, and try introducing a few at a time, so new fish don't get singled out. You will probably have some trial and error to find a balance that works. And you may find when the carpintis get large, they take up more of the 7' tank than you'd expect; for this reason I avoid breeding pairs when trying to do community tanks.