ok, bala sharks need to be in groups. ID sharks get HUGE depending on what species, and that catshark is a brackish fish and needs brackish water.
if you are set on those fish then i'd do 1 ID shark, 5 balas and 2 oscars and go from there.
if you are set on those fish then i'd do 1 ID shark, 5 balas and 2 oscars and go from there.