The feasibility of these combinations long term are probably not sustainable, even ina 500 gal tank.
Because each of these cichilds are very territorial as adults will probably come to blows at maturity.
As juvies they will probably be fine, until one or the other hits adulthood.
And each of those cichlids come from separate water parameters, but that aside.....
GTs are almost the only cichlid in the pH 7 waters they inhabitat west of the Andes, as adults when they come across eaach other in nature (unless they mate) there is usually a battle until one concedss and retreats, but in most tanks there is not that amount of escape spaceto prevent death.
Where midas come from in the pH 8 waters of the great lakes of Nicaragua, each male will carve out a territory of about 500 gallons, and if another cichlid enters within, there will be a similar battle to the one mentioned above.
Where JDs come from in the 7.5 pH, waters in the Cenotes of Mexico, when they are the dominent cichlid they do well, as in the video below, they do well
When they share similar Cenotes with othe domineering cichlids ( as below), as you can see, they don't do as well.
They are torn up, and populations are small, and only the strongest survive.
Oscars are the least territorial, but still require lots of space, minimum 6 ft tanks, all to themselves.

If you want to keep these 4 cichlids, I would suggest 4 separate tanks, of at least 6 ft in length each.
If you do decide to try your original concept, please post your success or failures........what ever happens, as an educational tool for others thinking of doing the same idea.
