I thought that they exist with rivulatus in the wild.
This true that they are found in the same area., but.....
Does it mean that they can exist in together in a small section of river(or tiny glass box) without conflict (maybe within 100 yards of each other)?
Or does it mean these territorial species stake out large areas that no other cichlid dares to cross, the size of a football field?
Because I collect cichlids in nature, I might often find a section of river, where I only net one of 2 cichlids (like the one below), in a football sized area.

There are certain species that are known to share habitat with a myriad of other cichlids.
Many of these are found in cichlid dense communities such as the eastern Amazon.
But where are talking about are species from western rivers on that side of the Andes. or certain rivers in Mexico or Central America, where only one or 2 cichlid species are found, this should tell you something about their ability to to coexist in the confines of a tank.
An example similar to the rivers west of the Andes, are the northern Pacific rivers in Mexico.
Mayaheros beanii, is the only cichlid in and near Mazatlan.

or Amphilophus istlanus near in rivers of the Rio Balsos drainage near Acapulco
Or an even more extreme isolation, Nandopsis haitiensus, the only cichlid species fpund on the island of Hispanioña

At one time possibly 1 million years ago, there may have been a number of cichlid species, but over time, only 1 species had the stamina to survive on that island.
Much like the cichlids from west of the Andes, the species above (among other loners) have well deserved reputations for for ¨not ¨playing well with other cichlds.
Take your cues from nature, if only 1 or 2 species exist in a large area in nature there is a reason. Or
If you know places like Amazon of the rift lakes in Africa have large communities coexisting together there may be a possibilty of combing.
I have always been drawn to the loners, so in the states I kept only one pair of cichlids per tank, and had 20 tanks to accomidate that loner bent.
