This is the issue: WHEN will all be made alive. That is; will receive immortality?
First is Christ, then those who are in Christ at His coming. Thinking that ALL will be immortalized at His Return, is wrong as we are clearly told that only the GT martyrs are raised back to life at that time. Revelation 20:4
It's not only the tribulation saints of Rev 20:4 that are resurrected immortal & incorruptible at Christ's coming. It is ALL the dead in Christ, and in FACT ALL the dead. That would include even those who physically die in Christ from Rev 20:6 "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." They aren't numbered with the souls alive after martyrdom, who had already lived and been martyred during this time symbolized a thousand years. But they too shall live with Christ before they die within this same symbolic period of time.
1 Corinthians 15:51-52 (KJV) Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed, In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
It's not only those who have physically died in Christ that shall be resurrected to life again at Christ' second coming. ALL that are in the graves shall be physically resurrected. Those who have done good, (died in Christ) resurrected to immortal life, and those who have done evil, resurrected for condemnation.
There shall not be two separate physical resurrections of ALL the dead. There is an order for the resurrection of ALL the physically dead that is coming. First the dead in Christ are resurrected immortal. Then all who are still physically alive at His coming will be caught up immortal with them. Then the rest of the dead, all who live and die in unbelief, shall also be resurrected to life again to stand before God at the GWTJ. They will be judged according to what is found written in the books and the book of life, their fate? The eternal flames of the lake of fire forever.
John 5:28-29 (KJV) Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation.
1 Thessalonians 4:16-17 (KJV) For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.