For a 40 breeder one pair of convicts and a school of larger tetra or danios, like Ivan said would be just fine. I would not recommend putting barbs, gouramis or the shark in there, keep it simple.
You have gotten plenty of good ideas and suggestions in the previous 8-10 posts you have made about the same theoretical tank. I have a feeling you will end up doing whatever you want, good luck with your tank.