Those who are of the true Christian faith will continue with Christ simply because of God's grace and mercy in His bestowing upon His chosen His faith.
The sticking point is the understanding of the word chosen. While I can't speak for everyone who believes in free will, I think most in that camp would say that God chooses everyone for communion with Himself, that is the experience of grace, theosis, salvation, sanctification. But this is an encounter that involves reciprocity--a relationship of person to Person. Personhood requires freedom of response. And that also entails the freedom to fail and miss the mark.
If God wanted all men to be saved, all men would be saved.
"Ye are my witnesses, saith the LORD, and my servant whom I have chosen: that ye may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me." -- Isaiah 43:10
Chosen so that we believe, not because we believe.
"According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love" -- Ephesians 1:4 "But we are bound to give thanks alway to God for you, brethren beloved of the Lord, because God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth" -- 2 Thessalonians 2:13 "So then it is not of him that willeth, nor of him that runneth, but of God that sheweth mercy." -- Romans 9:16 "Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God." -- John 1:13"Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you." -- John 15:16
Saved by grace through faith in Jesus Christ.
I would say this is against the very nature of God Himself as revealed in the Old Testament. God chose Abraham while his father was an idol maker and an idolater. He CHOSE Issac over Ishmael. He CHOSE Jacob over Esau. He CHOSE Joseph to protect the nation of Israel and Moses to bring them out. God didn't chose everyone in the Old Testament. If God could hardened the heart of Pharaoh, couldn't God have made Pharaoh repent? Why didn't He? Why would people think that the very nature and purpose of God as revealed in the Old Testament would change in the New?
God specifically chose Mary, John the Baptist and others. And there was no greater case of God choosing anyone then that of the apostle Paul who was very content to go about his merry way killing and imprisoning Christians. God put a stop to it and changed his heart. If God can blind the eyes of Paul so that he turned to Him and see, why doesn't He do it for Joe? Why do some get to hear the gospel and others don't? Why does our Lord Jesus states:
Every single person that God wants to be in heaven will be with him. Not one single sheep will be lost because their names have been written in the book of life not by their will but by the Father's will. The sheep are chosen by God actively seeking every single person in the Old and New Testament. Some give testimonies they've had a "burning bush" experience while others it is God quietly opening up their hearts like Lydia. But it is all the work of the Father.