I believe ALL who ever existed will be in God's Kingdom, although some will first have to through the LOF. I believe this because many scriptures teach that Jesus will save all, etc.
Here are some scriptures that support this doctrine.
1 John 4:14 14 And we have seen and testify that the Father has sent his Son to be the Savior of the world.
1 Timothy 4:10 For to this end we toil and strive, because we have our hope set on the living God, who is the Savior of all people, especially of those who believe.
Lamentations 3:31 For the Lord will not cast off forever
Romans 5:18 Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men.
1 Corinthians 15:22 For as in Adam all die, so also in Christ shall all be made alive.
Romans 11:32 For God has consigned all to disobedience, that he may have mercy on all.
John 12:32 And I, when I am lifted up from the earth, will draw ALL people to myself.”
Revelation 21:5 And he who was seated on the throne said, “Behold, I am making all things new.” Also he said, “Write this down, for these words are trustworthy and true.”
2 Corinthians 5:19 that is, in Christ God was reconciling the world to himself, not counting their trespasses against them, and entrusting to us the message of reconciliation.
John 6:51
I am the living bread that came down from heaven. If anyone eats of this bread, he will live forever. And the bread that I will give for the life of the world is my flesh.”
2 Corinthians 5:14-15 For the love of Christ controls us, because we have concluded this: that one has died for all, therefore all have died; 15 and he died for all, that those who live might no longer live for themselves but for him who for their sake died and was raised.
Colossians 1:20 and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.
John 3:17 For God did not send his Son into the world to condemn the world, but in order that the world might be saved through him.
Luke 3:6 and all flesh shall see the salvation of God
Philippians 2:10-11 so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
Romans 10:9 because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.
2 Samuel 14:14 We must all die; we are like water spilled on the ground, which cannot be gathered up again. But God will not take away life, and he devises means so that the banished one will not remain an outcast.
Ephesians 1:10 As a plan for the fullness of time, to unite all things in Him, things in heaven and things on earth.
John 1:29 The next day he saw Jesus coming toward him, and said, “Behold, the Lamb of God, who takes away the sin of the world!"
1 Corinthians 15:22-28
22 For as in Adam all die, so also in Christ shall all be made alive. 23 But each in his own order: Christ the firstfruits, then at his coming those who belong to Christ. 24 Then comes the end, when he delivers the kingdom to God the Father after destroying every rule and every authority and power. 25 For he must reign until he has put all his enemies under his feet. 26 The last enemy to be destroyed is death. 27 For “God[c] has put all things in subjection under his feet.” But when it says, “all things are put in subjection,” it is plain that he is excepted who put all things in subjection under him. 28 When all things are subjected to him, then the Son himself will also be subjected to him who put all things in subjection under him, that God may be all in all.
