How does Les Feltick reconcile whosoever will may come with chosen before the foundation of the world?
He does not fully reconcile them, calling the tension impossible for humans to understand. He brings the two together by saying that when a person responds to the whosoever-will invitation and exercises free will in the Gospel, heaven declares that God chose that person before the foundation of the world. The paradox remains in God's hands.
Les teaches that it is impossible for a human being to understand that over here we have the whosoever will may come, and over here we have chosen before the foundation of the world. The two are counter to the other, but they are not a problem for God, so he leaves it in God's hand. The best he can do is bring the two to the middle: yes, here we have the whosoever will; here we have the chosen from before the foundation of the world. Just as soon as you respond to the whosoever will and come to that invitation, the Lord Jesus shouts throughout all of heaven, "I chose Him before the foundation of the world." You exercised your free will when you responded to the Gospel, but on the other hand, God can honestly say, "I chose you before anything was ever created." Les calls that a glorious thought and says this is what the Word says: whosoever will may come, chosen from before the foundation of the world.