I am sure it has a lot to do with order and how long each fish is "alone" in the tank, as well as temperament of the fish each fish. The tank looks awesome by the way!
jar @ 12" is still very small. and in comparison, the gourami and jag are big, so i don't think ur jar would mess around w/'em. i had my gt and jd @ around 4-5" when my jar was about 12", and they did fine (providing w/enough shelter ofcourse)