I don’t know who gets to experience everlasting hellfire, but all indications are that they are those who reach out for sin instead of God; they reject His Grace. We understand that God’s Grace is for all men. God knows that some will reject Him; He will gather the many; he does not reject any man any more than the father of the prodigal son rejected him. But just as the prodigal son was enabled to return to his father, all men are enabled to come to God.
As to the virtuous pagans, that is outside our knowledge. We are instructed to evangelize and bring the Word of God to all. But what will happen to them is up to God; we will be judged on how many we have or haven’t brought the Word of God to. How many did we feed or clothe or visit? How did we treat the lest of our brethren?
He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. [Mat 5:45]
Is God powerful enough to save them all? Is God loving enough to save them all? Does God care that not all will come to him? Or does God have another plan for those who he knows will not become children of God?
God has said that he will save his own. The fact that some will not be saved means that they were never his own. They were his creation, but not his children. That is the difference. Man cannot thwart God. Man cannot surprise God. Man does not have a free will to choose God.