How can there be mortals in the millennial kingdom (pre-mill post trib)?

In light of passages like *1 Corinthians 15:52-53* which states that only **after** the “dead in Christ are raised” then those who are alive are “changed… putting on immortality” and the teaching on the judgement of the sheep and goats in *Matthew 25:31-46* which takes place at the inauguration of the Millennium, when the non-believers will “depart into eternal punishment” and believers into eternal life… **WHO will remain in perishable bodies (capable of reproducing) to repopulate the earth, thus producing the generations up to the final rebellion?** Whether you hold to a pre- mid- or post-tribulation rapture, there still stands the passage in *1 Corinthians 15* I cited above; you can’t allow for a parousia without first experiencing the resurrection or the putting on of immortality. This has been troubling me for a while, but I’ve concocted a few ways to marry these passages in light of post-trib eschatology… firstly; that “all” of Israel are converted just **after** the “harpazo” to fulfill *Zechariah 12:10* thus they won’t put on immortality. OR (THEORY) The multitude of victims of child sacrifice/abortion/infanticide are resurrected into an *edenic* state and those of us who have put on immortality are tasked with ruling them alongside Jesus with the rod of iron. Because they weren’t in-dwelt with the Spirit but (generally agreed upon) saved by grace nonetheless. Bonus: What do YOU suspect will happen when these fetuses/babies/children are bodily resurrected? Finally, what if there are pregnant believers that enter the millennial kingdom? And what of the children who haven’t reached the “age of accountability?” Thanks in advance!