1 Corinthians 15:22 For as in Adam all die, even so in Christ shall all be made alive. 23 But every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming. 24 Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
In this passage in 1 Corinthians, the times of resurrection are compared to the times of harvest. The biblical harvest was made up of three distinct parts: the firstfruits, the main harvest, and the gleanings. Therefore, it would make sense if the resurrection was also made up of three parts. Christ identifies the time of His resurrection as the time of the firstfruits. The time of the coming of Christ (both in the rapture and the revelation) would match the time of the main harvest. The gleanings would be at the end of the thousand year reign of Christ.
I am not sure, but the Old Testament saints may already be resurrected. If this is so, then they were part of the firstfruits that went up with Christ.
Matthew 27:51 And, behold, the veil of the temple was rent in twain from the top to the bottom; and the earth did quake, and the rocks rent;
52 And the graves were opened; and many bodies of the saints which slept arose, 53 And came out of the graves after his resurrection, and went into the holy city, and appeared unto many.
This passage in Matthew described the bodily resurrection of Old Testament saints. It is not clear if it is all Old Testament saints resurrected (though "many" can refer to all as in "many be dead" in Romans 5:15) and it is not clear if they went back to their graves or not, but it is definitely a bodily resurrection. Notice also that they came out of their graves after the resurrection of Christ (v.53) and not at the time of His crucifixion. I am not settled on this, but it is an interesting possibility and it would explain passages like the following:
Ephesians 4:8 Wherefore he saith, When he ascended up on high, he led captivity captive, and gave gifts unto men. 9 (Now that he ascended, what is it but that he also descended first into the lower parts of the earth?
10 He that descended is the same also that ascended up far above all heavens, that he might fill all things.)
At the least, this refers to the emptying of Abraham's bosom in the heart of the earth so that the souls of the Old Testament saints go to heaven. However, it may also refer to a bodily resurrection. And, in this case, their judgment for rewards may already be taken care of. However, it is also possible that they will be judged at the same time as the New Testament saints.
If there are millennial saints who die during the thousand year reign, they could easily be resurrected at the end of the kingdom age and judged
then. However, I am not sure that kingdom saints will die. Isaiah 65:20 states, "There shall be no more thence an infant of days, nor an old man that hath not filled his days: for the child shall die an hundred years old; but the sinner being an hundred years old shall be accursed." This verse tells us that someone who dies at a hundred years old will be considered a child. Evidently, life spans go back to pre-flood levels. Certainly, some of the saints may die, but I believe they will be in the minority. The millennium will only be a thousand years long and pre-flood ages often exceeded 900 years. The number to resurrect will probably be few. I think that those who are faithful to Christ may not die at all, but this is some speculation on my part.
The passage in Revelation concerning the kingdom age does not make any clear provision for saints who die after the tribulation. Revelation 20:6 states, "Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years." This is another reason I believe there will be few or none of the saints who die during this time. Finally on this topic, I believe that those who remain faithful to King Jesus through the time of the kingdom will actually become God's earthly people. They will repopulate the earth and will succeed where the first Adam failed. When the Son of man came "to seek and to save that which was lost" (Luke 19:10), that included the original earthly paradise. It, too, will be restored with the new earth. Its inhabitants must come from somewhere. I believe the new heaven will be populated by the earthly kingdom age saints. They may never need to be resurrected as such. Of course, in some way, they must receive a glorified body of sorts (though perhaps not quite like ours as this might be unnecessary for an earthly continuation), but this would be no problem for God (He will rapture saints from this age).
I admit to some guessing in these answers. However, I am not sure that God has revealed all of these answers to us (as per Deuteronomy 29:29). In that sense, we still see through a glass darkly. I am not sure that God thinks we need to know all these things. It reminds me of the time after the resurrection when Peter was set on knowing what would happen to John. Jesus told him, "If I will that he tarry till I come, what is that to thee? follow thou me" (John 21:22). I do not think that God minds us considering these subjects and meditating on them, but I do not think He would want us to concern ourselves too highly over such matters concerning other peoples. We must learn to just follow Him.