So you don't want to add unnecessary salts, yet you suggest adding 2 unnecessary salts. That really adds up. Oh? The name epsom salt wasn't a dead giveaway to you?
The sulfate you're adding is unnecessary, even in soil. Why not just use limestone or super phosphate (monocalcium phosphate)? Oh right, it's because you bought a bag of gypsum already, therefore everyone else should get a bag too. (even though their soil/nutrients have enough sulfur in it already)