I see your God doesn't know who the sheep goats are beforehand.If they get saved they are not lost sheep
and Christ does not mention lost sheep
You assume two things
One they are not God's sheep because of an established relationship with God i.e. Cornelius or Lydia
and if they got saved they were lost sheep previously
that's begging the question how one becomes God/Christs sheep
You really have to ask that question.
Isaiah 46:9-10 KJV
Remember the former things of old: for I am God, and there is none else; I am God, and there is none like me,  Declaring the end from the beginning, and from ancient times the things that are not yet done, saying, My counsel shall stand, and I will do all my pleasure:
If God can Declare the end from the begining. What is unknown to God.