Haitiensus are some of my favorites, but are not good community fish as adults.
My adult pair would not accept any other fish in a 6ft tank once they hit about 6-8".
And if they "can't" kill the intruder they usually get so stressed out they succumb to disease.
They also seem to need much higher temps than most other cichlids (high 80s) are not unusual for the water they live in on their island, and since they are the only endemic child to it, being unaccepting of other cichlids is not surprising.

Since there are more than 800 species (probably closer to 1000 or more these days) that are considered "New World" cichlids, I find it very difficult to narrow down a favorite.
If you are looking for a shoaling type the genus Thorichthys and Cribroheros are interesting because a group of 6 or more living without aggression can be fascinating.
Cribroheros rostratum below.

I am also interested in Rheophillic species so the genus Tomocichla, Rheohero, and Chuco also come to mind.

Chuco micropthalmus above, Tomocichla asfraci below

Rheoheros lentiginossa below

I also very much like the cold water cichlids of Uruguay, the GYmnogeophagis, Australoheros, and cold water pikes.

Red Ceibal above, Gymnogeophagus sp Paso Pache below

None of the above, could really be housed in the same tank, as condition requirements for each are totally different except maybe the Chucos, and Tomocichla, but then again, they'd see each other as competitors and probably off each other in time.