What is happening in Luke 9:27-36? Who are the two men talking with Christ? Were they resurrected?
The scene in Luke 9 with Christ, Moses and Elijah is not related in any way to resurrection or even glorification. Here's the story again:
Luke 9:27 “But I say to you truthfully, there are some of those standing here who will not taste death until they see the kingdom of God.”
Luke 9:28 Some eight days after these sayings, He took along Peter and John and James, and went up on the mountain to pray.
Luke 9:29 And while He was praying, the appearance of His face became different, and His clothing became white and gleaming.
Luke 9:30 And behold, two men were talking with Him; and they were Moses and Elijah,
Luke 9:31 who, appearing in glory, were speaking of His departure which He was about to accomplish at Jerusalem.
Luke 9:32 Now Peter and his companions had been overcome with sleep; but when they were fully awake, they saw His glory and the two men standing with Him.
Luke 9:33 And as these were leaving Him, Peter said to Jesus, “ Master, it is good for us to be here; let us make three tabernacles: one for You, and one for Moses, and one for Elijah” — not realizing what he was saying.
Luke 9:34 While he was saying this, a cloud formed and began to overshadow them; and they were afraid as they entered the cloud.
Luke 9:35 Then a voice came out of the cloud, saying, “ This is My Son, My Chosen One; listen to Him!”
Luke 9:36 And when the voice had spoken, Jesus was found alone. And they kept silent, and reported to no one in those days any of the things which they had seen.
Notice that immediately after the Father spoke in v.35, then Jesus is found alone. A moment earlier, two other men were seen standing beside Jesus. Furthermore, notice that the apostles were able to identify these two men as Elijah and Moses even though no one had mentioned their names. Remember, the Apostles could not have known who these men were by appearance, since no paintings or photos of these men existed.
Therefore, these two men were not standing in this moment in physical bodies. They were not "resurrected" people, much less resurrected Moses or Elijah. Moses and Elijah will not receive new bodies until the resurrection of the Old Testament saints at the end of Tribulation (see Daniel 12:1-2). Furthermore, the rapid appearance and disappearance of these "men" suggest they were either visions only or perhaps even angels presenting themselves as Elijah and Moses. Remember, angels commonly appear in the form of men (see Genesis 18).
Finally, consider the purpose of this moment in the Gospels. Jesus is showing Himself in His future, glorified form, which is the form He will have in the Kingdom. He was giving the Apostles a vision of the future Kingdom, in keeping with His promise from Luke 9:27. So the entire scene is structured as a vision of the future, with Jesus in His future form and Elijah and Moses also reprinted in their future form.So these men are not shown in a resurrected, glorified form. This scene is a "coming attractions" vision granted to the disciples to give them an understanding of the Kingdom to come. The visions of Elijah and Moses were likely not even these two men in reality but merely images given to the disciples to make a point (similar to the way John experienced visions of future events in Revelation).
Regarding the people raised from the dead at the resurrection of Jesus, they were raised in the same way that Lazarus was raised from the dead. These men returned to life in their original bodies, not into new, resurrected, glorified bodies. The purpose in their raising was to witness to the resurrection of the Messiah. Presumably, they lived for a time and then eventually died again (like Lazarus). Again, this situation has no relationship to the resurrection of the Rapture or Tribulation.
Regarding the saints seen in the throne room of Revelation 7, the elders represent the Church saints as we explained earlier. The fact that the full compliment of elders (24) are present in Heaven along with the Seven Spirits of God in Revelation 4 leads us to conclude that the entire church has been raptured into new bodies and is also present in the throne room prior to the start of Tribulation.
By the time we reach Revelation 7, the Tribulation has begun on earth, and of course the Church saints are still in Heaven awaiting Christ's return. As Tribulation takes place, saints are martyred and enter into Heaven in spirit form only. They do not receive new bodies until the end of Tribulation (see Daniel 12:11-12).
So while they are in Heaven, they can be seen and share the company of the Church Saints, but they do not have new bodies yet. They live in Heaven in the same way Church saints who die today live in Heaven prior to the Rapture: in spirit form only. We see both the Church and the martyred saints of Tribulation represented in Heaven. The church saints are represented by their elders, while the martyred saints are seen in spirit form under the altar in Revelation 6 and again at the end of chapter 7.