I understand from my studies that there are 3 groups of saints, Old testament saints who believed in a coming Messiah, Church saints, who come to the Lord between Pentecost and the Rapture, and Tribulation Saints who believe in Him after the Rapture but before the 2nd Coming. When is each group given glorified bodies? I know that the Church/Bride is given glorified bodies at the Rapture – but what about the others? And where do we/they all reside in the years between the (pre-trib) Rapture and the New Heaven & Earth after the Millennium?
You’re correct in saying that all Church Age saints will receive glorified bodies at the rapture/resurrection. We will reside in the New Jerusalem. Old Testament saints will receive their new bodies at the time of the 2nd Coming (Daniel 12:2) and will dwell in Israel. Tribulation saints who are martyred will receive new bodies along with Old Testament saints at the time of the 2nd Coming (Rev. 20:4-5), and will serve the Lord in His Temple (Rev. 7:14-15). Tribulation Saints who survive in their natural state will re-populate the nations on Earth during the Millennium. (Matt. 25:34)
But you must look at Rev. 21-22 again. The first verses of each chapter are virtual copies of the Old Testament, put there to show you that John was speaking of Earth at the beginning of the Millennium, not its end. It’s confusing because Rev. 20:7-15 is a parenthetical passage John used to follow two thoughts to their conclusion; the final disposition of Satan and the 2nd resurrection.
Then, beginning in Rev. 21 he went back to describe the Millennium including the New Jerusalem, home of the Church, and the restored Earth, home of redeemed Israel and Tribulation Saints. We know this partly because Rev. 21:1 is a direct quote from Isaiah 65:17 where the context is the Millennium, and Rev. 22:1-7 is taken from Ezekiel 47:1-12, another Millennial passage. Time is also referenced in Rev. 22:2 with the tree bearing 12 crops of fruit one each month, and eternity by definition is the absence of time.