I agree, a male jaguar cichlid will likely test your GT's once he gets to a certain size. Depending how fast your GT's will grow (usually very slowly) you certainly run the risk of losing them at some point.
A Green Terror will breed with a Blue Acara (very similar), but that's about it. Generally speaking, South American cichlids cannot breed outside of their species whereas Central Americans will readily breed. The exception, as previously stated is the Festae (Red Terror). In my opinion this is just a Central American living in South American waters.
In terms of your current compatibility, my advice would be to either deck out your aquarium with hiding places or to acquire more Cichlids. The Jaguar is known to stalk and hunt its competitors, so ensure that the given sanctuaries are too small for the Jag to intrude. In terms of adding cichlids, the concept would be adding a few slightly larger cichlids to help divide the aggression and at some point, remove them. This enhances the possibility of the Jag becoming more tolerant of tank mates.
