I agree with the others that say only a pair, although I would start out with @ half dozen juvies, and allow a pair to form from the group .
200 L is pretty small. But if you mean EB Acara being domestic line-bred/man made form, they "may" be slightly less territorial, compared to the natural form.
I have an 800L tank with wild caught Panamanian Acara's (Andinoacara coerleopunctatus) that are very similar in all aspects of aggressiveness and territoriality. The tank started out with 15 adults,, two of the most alpha males immediately killed 3 slightly more subbordinate males, and over the last year and a half, whittled the tank to two males, each claimed a separate territory on each opposite ends of the tank (50%) , and 5 females.
As far as other fish, I wouldn't add other cichlids, only some geographically correct dithers, such as tetras, or large live bearers, that use the surface area as the normal place in that water column.
Here is a video of one side of the tank.
Panamanian Tank
now the other end where the male Andinoacara is keeping others out.
Andinoacara coerleo