Saints are in heaven at the time before the return of the Messiah Jesus. They are referred to in Revelation chapter 6. But they are referred to as Saints who have been killed for their faith in Jesus.
9 When He opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the testimony which they held. 10 And they cried with a loud voice, saying, "How long, O Lord, holy and true, until You judge and avenge our blood on those who dwell on the earth?" 11 Then a white robe was given to each of them; and it was said to them that they should rest a little while longer, until both the number of their fellow servants and their brethren, who would be killed as they were, was completed.
It does not say that all saints go to heaven. It refers to only those who have been killed for their faith.
As for satan being in hell for 6000 years that is a tradition of man it is not biblical at all. I have posted Revelation 20 below with some thoughts added.
1 Then I saw an angel coming down from heaven, having the key to the bottomless pit and a great chain in his hand. 2 He laid hold of the dragon, that serpent of old, who is the Devil and Satan, and bound him for a thousand years; 3 and he cast him into the bottomless pit, and shut him up, and set a seal on him, so that he should deceive the nations no more till the thousand years were finished. But after these things he must be released for a little while.
You see satan, is not in hell. When the Messiah Jesus returns satan will be cast into the bottomless pit for 1000 years. After the 1000 year reign of the Messiah Jesus satan will be released from the pit to go out and deceive the world one more time.
4 And I saw thrones, and they sat on them, and judgment was committed to them. Then I saw the souls of those who had been beheaded for their witness to Jesus and for the word of God, who had not worshiped the beast or his image, and had not received his mark on their foreheads or on their hands. And they lived and reigned with Christ for a thousand years. 5 But the rest of the dead did not live again until the thousand years were finished. This is the first resurrection. 6 Blessed and holy is he who has part in the first resurrection. Over such the second death has no power, but they shall be priests of God and of Christ, and shall reign with Him a thousand years.
True Christians will be resurrected upon the return of the Messiah Jesus and from that day on they will never die again. They will live and rule with Jesus for 1000 years on earth. But the rest of the dead will not be resurrected until the 1000 years is up and the final satanic rebellion in defeated. Those who are raised from the dead at the Messiah Jesus return are assured they will not face the second death (lake of fire)
7 Now when the thousand years have expired, Satan will be released from his prison 8 and will go out to deceive the nations which are in the four corners of the earth, Gog and Magog, to gather them together to battle, whose number is as the sand of the sea. 9 They went up on the breadth of the earth and surrounded the camp of the saints and the beloved city. And fire came down from God out of heaven and devoured them.
At the end of the 1000 years satan will go out into the world once again to deceive the world again and lead them in an attack on the “camp of the saints” (resurrected saints on earth) and the beloved city (Jerusalem) But there attack will be in vain because God will destroy them.
10 The devil, who deceived them, was cast into the lake of fire and brimstone where the beast and the false prophet are. And they will be tormented day and night forever and ever.
Note how it says satan (devil) will be cast into the Lake of Fire this happens 1000 years after the return of the Messiah After the defeat of the final satanic rebellion. Note it also says that the beast and false prophet are already there? The beast and the false prophet are men they will be cast into the lake of fire at the start of the Messiah’s 1000 year reaign. The beast is both a man and the empire he leads He is also commonly known as the anti-christ the false prophet will deceive the world and fool people into thinking the anti-christ is the returned Messiah.
11 Then I saw a great white throne and Him who sat on it, from whose face the earth and the heaven fled away. And there was found no place for them. 12 And I saw the dead, small and great, standing before God, and books were opened. And another book was opened, which is the Book of Life. And the dead were judged according to their works, by the things which were written in the books. 13 The sea gave up the dead who were in it, and Death and Hades delivered up the dead who were in them. And they were judged, each one according to his works.
Now this is the final resurrection when all peoples that have ever lived will be raised from the dead to face judgment. But as said before those who took part in the first resurrection will not face this judgement. Note how it says Death and Hades. Death and Hades are not the same thing
14 Then Death and Hades were cast into the lake of fire. This is the second death. 15 And anyone not found written in the Book of Life was cast into the lake of fire.
Hades is hell the place spoken off by Jesus in His parable of Lazarus. Hades is not The Lake Of Fire because it is going to be cast into the Lake Of Fire. You cannot cast something into itself.
22 "So it was that the beggar died, and was carried by the angels to Abraham's bosom. The rich man also died and was buried. 23 "And being in torments in Hades, he lifted up his eyes and saw Abraham afar off, and Lazarus in his bosom. 24 "Then he cried and said, 'Father Abraham, have mercy on me, and send Lazarus that he may dip the tip of his finger in water and cool my tongue; for I am tormented in this flame.'
All Praise The Ancient Of Days