How can one get rid of the envy that drives a person to hate others if he feels they will become like him in religiosity, and did the Salaf do such a thing?

The blameworthy feeling of disliking good for others stems from the whispers of Satan, aiming to discourage you from inviting people to Allah. Its cure lies in knowing that grace is in Allah's hand, and that this dislike may nullify your acts of obedience and lead to loss. You must strive to love for your brothers what you love for yourself, for this is a great act of obedience. The blameworthy envy of others drawing closer to Allah is a form of jealousy and arrogance. Allah loves for all His creation to worship Him. True love for Allah necessitates your love for all creatures to share with you in His obedience. You must strive to repel this envy. The stronger your love for Allah in your heart, the more you will love for His servants to obey their Lord, and you will compete with them in goodness rather than preventing them. Remember that when you teach someone a good deed or invite them to a virtue, their reward will also be in the balance of your good deeds. Turn to your Lord, gather more good deeds, compete in obedience, love good for creation, and rid yourself of these satanic thoughts, seeking Allah's help.