The wonderful answer to the last part of the question is yes, they can be saved. God “desires all men to be saved and to come to the knowledge of the truth” (1 Timothy 2:4 1 Timothy 2:4Who will have all men to be saved, and to come to the knowledge of the truth.
American King James Version×). He says further, “The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance” (2 Peter 3:9 2 Peter 3:9The Lord is not slack concerning his promise, as some men count slackness; but is long-suffering to us-ward, not willing that any should perish, but that all should come to repentance.
American King James Version×).
Yet we know that countless millions have lived and died with-out knowing this one clear biblical fact about salvation: “Salvation is found in no one else, for there is no other name under heaven given to men by which we must be saved” (Acts 4:12 Acts 4:12Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.
American King James Version×, New International Version). This name, of course, is Jesus Christ.
The amazing truth is that a future resurrection is coming for this one great purpose—to offer eternal life to those who lived their entire lives without knowing the true God and His Son.
Scripture shows that God will bring the vast majority of humanity back to physical life and give them their opportunity for salvation by allowing them to learn about His plan and purpose and to come to know Him and His Son. Please note this prophecy in Ezekiel 37:1-14 Ezekiel 37:1-14  The hand of the LORD was on me, and carried me out in the spirit of the LORD, and set me down in the middle of the valley which was full of bones,
 And caused me to pass by them round about: and, behold, there were very many in the open valley; and, see, they were very dry.
 And he said to me, Son of man, can these bones live? And I answered, O Lord GOD, you know.
 Again he said to me, Prophesy on these bones, and say to them, O you dry bones, hear the word of the LORD.
 Thus said the Lord GOD to these bones; Behold, I will cause breath to enter into you, and you shall live:
 And I will lay sinews on you, and will bring up flesh on you, and cover you with skin, and put breath in you, and you shall live; and you shall know that I am the LORD.
 So I prophesied as I was commanded: and as I prophesied, there was a noise, and behold a shaking, and the bones came together, bone to his bone.
 And when I beheld, see, the sinews and the flesh came up on them, and the skin covered them above: but there was no breath in them.
 Then said he to me, Prophesy to the wind, prophesy, son of man, and say to the wind, Thus said the Lord GOD; Come from the four winds, O breath, and breathe on these slain, that they may live.
 So I prophesied as he commanded me, and the breath came into them, and they lived, and stood up on their feet, an exceeding great army.
 Then he said to me, Son of man, these bones are the whole house of Israel: behold, they say, Our bones are dried, and our hope is lost: we are cut off for our parts.
 Therefore prophesy and say to them, Thus said the Lord GOD; Behold, O my people, I will open your graves, and cause you to come up out of your graves, and bring you into the land of Israel.
 And you shall know that I am the LORD, when I have opened your graves, O my people, and brought you up out of your graves,
 And shall put my spirit in you, and you shall live, and I shall place you in your own land: then shall you know that I the LORD have spoken it, and performed it, said the LORD.
American King James Version×where God gives to Ezekiel an astounding vision of the resurrection to physical life of the nation of Israel:
“The hand of the Lord came upon me and brought me out in the Spirit of the Lord, and set me down in the midst of the valley; and it was full of bones. Then He caused me to pass by them all around, and behold, there were very many in the open valley; and indeed they were very dry. And He said to me, ‘Son of man, can these bones live?’ So I answered, ‘O Lord God, You know.’
“Again He said to me, ‘Prophesy to these bones, and say to them, “O dry bones, hear the word of the Lord! Thus says the Lord God to these bones: ‘Surely I will cause breath to enter into you, and you shall live. I will put sinews on you and bring flesh upon you, cover you with skin and put breath in you; and you shall live. Then you shall know that I am the Lord.’”’”
Clearly what we are reading about here is a resurrection of people long dead to a physical life. Continuing:
“So I prophesied as I was commanded; and as I prophesied, there was a noise, and suddenly a rattling; and the bones came together, bone to bone. Indeed, as I looked, the sinews and the flesh came upon them, and the skin covered them over; but there was no breath in them. Also He said to me, ‘Prophesy to the breath, prophesy, son of man, and say to the breath, “Thus says the Lord God: ‘Come from the four winds, O breath, and breathe on these slain, that they may live.’”’
“So I prophesied as He commanded me, and breath came into them, and they lived, and stood upon their feet, an exceedingly great army. Then He said to me, ‘Son of man, these bones are the whole house of Israel. They indeed say, “Our bones are dry, our hope is lost, and we ourselves are cut off!” Therefore prophesy and say to them, “Thus says the Lord God: ‘Behold, O My people, I will open your graves and cause you to come up from your graves, and bring you into the land of Israel. Then you shall know that I am the Lord, when I have opened your graves, O My people, and brought you up from your graves. I will put My Spirit in you, and you shall live, and I will place you in your own land. Then you shall know that I, the Lord, have spoken it and performed it,’ says the Lord.”’”
Note what this passage teaches us. God asked Ezekiel if these dead Israelites could live again, and then in vision God puts sinews, flesh and skin on the dead bones and breathes the breath of life back into them and they come alive. Then God gives them His Holy Spirit to guide them, to obey Him and to do His will.
Once given the Holy Spirit, these people will live on the earth for a period of time and will be judged for their works. They will not be condemned to eternal hellfire for the sins of their past lives when they did not know God. Rather, they will be judged for their behavior at this future time in man’s history.
And by extension, if God is going to provide a way to save ancient Israel, He will also offer all gentiles the same plan of salvation (Luke 2:30-32 Luke 2:30-32  For my eyes have seen your salvation,
 Which you have prepared before the face of all people;
 A light to lighten the Gentiles, and the glory of your people Israel.
American King James Version×). We know this because the Word of God says repeatedly that God shows no partiality (Acts 10:34 Acts 10:34Then Peter opened his mouth, and said, Of a truth I perceive that God is no respecter of persons:
American King James Version×; Romans 2:11 Romans 2:11For there is no respect of persons with God.
American King James Version×; Ephesians 6:9 Ephesians 6:9And, you masters, do the same things to them, forbearing threatening: knowing that your Master also is in heaven; neither is there respect of persons with him.
American King James Version×). Regarding salvation, all peoples have an equal opportunity.
This resurrection is also described in Matthew 11:20-24 Matthew 11:20-24  Then began he to upbraid the cities wherein most of his mighty works were done, because they repented not:
 Woe to you, Chorazin! woe to you, Bethsaida! for if the mighty works, which were done in you, had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes.
 But I say to you, It shall be more tolerable for Tyre and Sidon at the day of judgment, than for you.
 And you, Capernaum, which are exalted to heaven, shall be brought down to hell: for if the mighty works, which have been done in you, had been done in Sodom, it would have remained until this day.
 But I say to you, That it shall be more tolerable for the land of Sodom in the day of judgment, than for you.
American King James Version×, where Jesus explained that long-dead inhabitants of the sinful cities of Sodom, Tyre and Sidon would have repented at His preaching if they had had the opportunity. At last they will have that opportunity. (See also Matthew 12:41-42 Matthew 12:41-42  The men of Nineveh shall rise in judgment with this generation, and shall condemn it: because they repented at the preaching of Jonas; and, behold, a greater than Jonas is here.  The queen of the south shall rise up in the judgment with this generation, and shall condemn it: for she came from the uttermost parts of the earth to hear the wisdom of Solomon; and, behold, a greater than Solomon is here.
American King James Version×.)
The same resurrection is also described in the vision of the Great White Throne in Revelation 20:11-15 Revelation 20:11-15  And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them.
 And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.
 And death and hell were cast into the lake of fire. This is the second death.
 And whoever was not found written in the book of life was cast into the lake of fire.
American King James Version×—the judgment here being a period of evaluation as people learn to live by the Scriptures, not an immediate sentencing.
In the end the evil works of Satan will be defeated by the power and mercy of God. Ultimately, it will not be untold masses of people who ultimately reject God and suffer the fate of eternal death. Rather, most of humanity will come to understand and know God and the depth of God's mercies through Jesus Christ, and they also will come to repentance.
This short response gives only a brief overview of a great biblical truth revealing God’s mercy regarding untold billions who have died without understanding forgiveness through Jesus Christ.
At our website we have several articles and studies on this important subject. If you would like to study the topic further, search for “second resurrection”.
These articles will show you more biblical proof that in God’s great plan there is indeed an opportunity for all to receive God’s gift of salvation. And may God continue to bless you as you strive to learn more about Him.