No, adding that few fish to that large a tank will not cause that great a change in pH.
Better to control the GH and KH instead and let the pH alone.
For the fish you list GH and KH anywhere from 3 German degrees of hardness to about 5 would be optimum, and up to about 9 degrees would be OK for hatchery raised fish.
What is the GH and KH of the tap water, and of the tank?
I will double check again to make sure I have correct gh & kh reading ....