All Israel are not born again believers. Just as the difference between and outward Jew in respect to the flesh and one as a believer in respect to a inward born again person.
Not sure why you use free will? Its in light of the gospel the will of God. It is God who does soften a persons heart that is in bondage to do the will of the god of this world. He performs that which he appoints to us.. . . . a imputed righteousness having nothing to do with ethnicity.
Mankind was created to do the will of another. Never as a free will agent.
In that sense, we can speak of the olive tree as “the Israel of God,” as Paul elsewhere refers to the community of Jews and Gentiles who follow Christ by this name .
Galatians 6:16 And
as many as walk according to this rule, peace be on them, and mercy, and upon the
Israel of God.
Salvation has nothing to s do with the flesh of any nation. The Jews were used in various parables as types and shadows to teach how to believe (faith) and recognize unbelief (no faith ) representing mankind as a whole. When a person begins glorying in the flesh of a nation .The gospel has lost its effect having become subject to do the will of this world a will in bondage ..