In 203G you can house just about whatever you want provided your up to the task of providieng those fish with their individual (uniqe) needs. Personally, id keep some big monster fish, but its really up to personal opinion. If the tank is brand new it will need time to cycle anyway, maybe use this time to sleep on it.
The thing about bala sharks is that when they get scared the freeze and dont move, they can die if not revived. All three of mine died from " freezing". I would personally get some kribs, or another dwarf cichlid and some red turquise discus and some tetras and of course live plants, your tank would look abosolutly stuning!
Oh.. a tank that big can hold a lot more tetras then 200... I would say
50 true rummynose tetras
50 Cardinals tetras
50 Bleeding heart tetras
50 phantom tetras
And some other types of fish
keep in mind. you can stock as many fish as you want in it as long as yu have the plant power to remove the nitrAte from said fish. That is the true method of figuring your stocking levels.