Yes, I can't agree more. Americans require length and well established territory. Your JD and convicts etc would be fine, but nothing more aggressive than a JD. Truthfully JD's as a whole are not that nasty. But like any fish they are different temperaments. You could always attempt a tank with 2 Electric Blue JDs and try for a pair. Would be a rewarding effort. But unless you are very specific in your stock and timeline for it, Africans would do best in a tank like yours. Tank is only wide in the front and the odds your big fish only swim back in forth in the front are slim. The space where the structure is, is actually quite narrow. There are some very groovy Africans your buddy can show you. You might even consider changing your background to a solid color to enhance theirs.
Best of Luck