Judging from the fact that there are also several african cichlids in that tank (two are visible in your picture), I wouldn't be so sure that that is a South American cichlid...
Stressed out convict? Seems a bit wierd colored. Hybrid of unknown linage? I would not bet either way right now. One way fish wind up in the "assorted" tank is when nobody knows or can say.
I would not normally recommend convicts for a planted tank. They do have some real attitude problems. Fish with names like "convict" often do have more fight than we like.
Very possible.The only other thing I could see this being is a HRP/convict mutt