What will happen to all the Gentile people that died before Christ was born? They did not get the opportunity to hear the Word or be welcomed into the family of God.
I will begin by correcting your last two points, for as we shall see some Gentiles “DID get the opportunity to hear the Word and to be welcomed into the family of God.” One clear example of this is found in NOAH, for we read in Genesis 6:8-9, “But NOAH found grace in the eyes of the LORD…NOAH was a JUST man, perfect in his generations.” Here we learn that Noah, a Gentile who lived long before the nation of Israel was called into existence, was a “JUST man.” This means that he was accounted RIGHTEOUS by God. How did that happen? We know from Scripture that men are JUSTIFIED by faith and that “FAITH comes by hearing, and hearing by the word of God” (Romans 10:17). It is obvious that Noah heard the word of God and BELIEVED IT! Hebrews 11:7 speaks to this, “By FAITH Noah, being DIVINELY WARNED OF THINGS NOT SEEN, moved with godly fear, prepared an ark for the saving of his household, by which he condemned the world and became HEIR OF RIGHTEOUSNESS WHICH IS ACCORDING TO FAITH.”
Now let’s consider Abraham, who was a GENTILE when he was accounted righteous by God. We read in Genesis 15:4-6, “And behold, THE WORD OF THE LORD CAME TO HIM, saying, ‘This one shall not be your heir, but one who will come from your own body shall be your heir.’ Then He brought him outside and said, ‘Look now toward heaven, and count the stars if you are able to number them.’ And He said to him, ‘So shall your descendants be.’ And HE BELIEVED IN THE LORD, AND HE ACCOUNTED IT TO HIM FOR RIGHTEOUSNESS.’” The apostle Paul was inspired to speak of this in Romans 4:1-3, “What then shall we say that Abraham our father has found according to the flesh? For if Abraham was justified by works, he has something to boast about, but not before God. For what does the Scripture say? ‘Abraham BELIEVED GOD, and it was accounted to him for righteousness.’” Abraham is set forth in Scripture as a pattern for ALL MEN, teaching us that “all men must BELIEVE God’s Word in order to be JUSTIFIED before Him.” Galatians 3:6-9 is a commentary on this truth: “Just as Abraham ‘believed God, and it was accounted to him for righteousness.’ Therefore, know that only those who are of faith are sons of Abrahams. And the Scripture, foreseeing that God would JUSTIFY THE GENTILES BY FAITH, preached the gospel to Abraham beforehand, saying, ‘In you all the nations shall be blessed.’ So, then, those who are of faith are blessed with believing Abraham.”
After the nation of Israel was born Gentiles were still “saved by faith in God’s word.” Rahab is a good example of this for though she was a Gentile harlot, yet she came to believe in the “One true God through the nation of Israel.” She believed the report that God was about to judge the city of Jericho and thus we read, “By FAITH the harlot Rahab did not perish with those who did not believe, when she received the spies with peace” (Hebrews 11:31). She also, by the amazing grace of God, married a Jewish man and was in the godly line in which Jesus Christ was born (see Matthew 1:1-6). We see then that she, a Gentile, “did get the opportunity to hear the word of God and to be welcomed into the family of God.”
We could cite other examples of Gentiles hearing the word of God and being blessed through faith, but I will only cite one more. If you read the book of Jonah, you will see that God sent Jonah to announce that He was about to judge the city of Nineveh for their wickedness (Jonah 1:1-2). Jonah did preach to the city (see 3:3-4) and then we read that “the people of Nineveh BELIEVED GOD, proclaimed a fast, and PUT ON SACKCLOTH, from the greatest to the least of them” (verse 5)! Because of their FAITH and REPENTANCE, God did not judge them (see verse 10).
In closing, there are surely multitudes of Gentiles that lived before Christ was born who never heard the word of God. This begs the question, “Could they still be welcomed into the family of God?” I would encourage you to read Romans 1:18-2:15, for in those verses the apostle Paul contemplates Gentiles who never heard the word of God, yet they will still be “judged by God” for the light they were given. The LIGHT OF CREATION is seen in 1:18-20 and the LIGHT OF CONSCIENCE is seen in 2:12-15. If men refuse to acknowledge God as their Creator through the “light of creation” or acknowledge their sin through the “light of conscience,” they will be without excuse in the day of judgment. Yet this seems to indicate that IF MEN DO ACT on the “light of creation” and the “light of conscience” they will not be judged in the day of judgment. Perhaps, before they die, God will then send them the greater “light of the gospel” so they can believe it and be saved. Or, perhaps, if men die before then God will take into account their faith in Him as Creator and their desire to act on the dictates of their conscience and save them. Remember, God didn’t judge Nineveh even though, as far as we know, they never heard a “gospel message” (they heard a “message of judgment”). Yet they did “act on the light that was given to them” and this is how God will deal with all men, whether they be Jews or Gentiles, and no matter what age they lived in. (482.1) (DO)