If they were resurrected with immortal bodies then Paul would have mentioned that when he gave the order of bodily resurrections unto immortality, but he didn't. So, they must have died again later like Lazarus did.
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.
Of course they are mentioned. They are the firstfruits (plural).
Christ was never made alive. Only those under the punishment of death, in Adam, were the firstfruits, made alive. Christ never knew sin by being born into corruption. 2 Corinthians 5:21
"For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him."
The only time Jesus knew sin, and experienced death was as God, on the Cross. Not that Jesus was born a sinner with a corruptible physical body. Jesus was resurrected into the same permanent incorruptible physical body, He died on the Cross with. His old body did not return to dust, because it was not of death.
You do understand that those redeemed in Paradise are only in Paradise because they have been made alive, not waiting to be made alive? Why would God allow death into Paradise? From the Flood until the Cross, God made souls wait in the valley of the shadow of death, tasting death, in Abraham's bosom. How did that change at the Cross, if no has been made alive yet?
Are you saying all can wait in heaven, in the same condition as in Abraham's bosom not yet made alive? Why could they not wait in heaven before the Cross then? Do you not understand that the OT had to be made alive in order to leave Abraham's bosom and enter heaven? Ephesians 4:8-10
"Wherefore he saith, When he ascended up on high, he led captivity captive, and gave gifts unto men. Now that he ascended, what is it but that he also descended first into the lower parts of the earth? He that descended is the same also that ascended up far above all heavens, that he might fill all things."
The OT came out of their graves in permanent incorruptible physical bodies. That was the gift of being the firstfruits of all the redeemed. This descending and ascending, was immediate in a twinkling of an eye, like the rapture. They came out of their graves instantly all over the earth, wherever they had lived. God leaves no one behind. It was a complete job, with the gift of eternal life to all those in Abraham's bosom, not just those who came out in Jerusalem, recorded by Matthew.
Why do you think Jesus is the resurrection and temporary life, and that the redeemed keep dying over and over again, just because you say so? Jesus did not need to be made alive; resurrected, yes. Was that a temporary resurrection? Then why are those made alive just a temporary resurrection? Being made alive at the Second Coming is only for those dead living on the earth in a mortal body of death. Not those in Paradise who have already been made alive, because that is the only way they can even be in heaven. No one can enjoy heaven waiting to be made alive. That was what Abraham's bosom was for in sheol.
Paul said that to be absent from the body, the soul, was to present with the Lord, not waiting in death, Abraham's bosom, nor some form of purgatory, because one is waiting to be made alive.
The hour of being made alive started with Lazarus and has been ongoing ever since.
"Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life. Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God: and they that hear shall live."
Everlasting life is being made alive. You don't change bodies with the second birth, you change spiritual families. The redemption of the body and being made alive is when the soul leaves this body of death, and enters God's permanent incorruptible physical body. 2 Corinthians 5:1
"For we know that if our earthly house of this tabernacle were dissolved, we have a building of God, an house not made with hands, eternal in the heavens."
Paul is saying we should know what being made alive is from his first book to Corinth. Being made alive is receiving the first resurrection upon physical death, because one has the second birth certificate saying they belong to the family of God, prior to the redemption of the body. Back to Ephesians 4:30
"And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption."
The Holy Spirit does not continue to seal the soul in some waiting pattern, waiting for a single last hour for physical resurrection. Once one enters heaven after a first resurrection into a permanent incorruptible physical body, they are made alive and no longer need the Holy Spirit telling them how to enjoy Paradise.
Having the seal of the Holy Spirit only pertains to this mortal condition of death, as mortal means death.
"And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ."
In 1 Thessalonians 4, Paul was expecting to be alive at the Second Coming, so which physical body was Paul talking about in chapter 5? Did Paul say this natural mortal body needed to be preserved for thousands of years in a grave waiting for a resurrection? NO! A thousand times no. Paul was talking about living circumspect prior to physical death in this mortal body. Once the soul leaves death behind for eternal life, the soul is placed in a permanent incorruptible physical body, that does not need to be preserved blameless.
The difference between a natural body and a spiritual body is that one came from Adam of death, and the other comes from God of eternal life, the soul being made alive by putting on this body from God, also known as the first resurrection.