The Church is promised exemption from God's judgmental wrath (1 Thess 1:10; 5:9). But, God's judgmental wrath is poured out during the tribulation.Second, as to non-glorified bodies, Scripture shows that some people will enter the millennial kingdom in natural bodies and then give birth to children (Isa 65: 20). Some of those children will rebel against the Lord (Rev 20:7-10). But, people in glorified bodies cannot give birth, nor do they sin. Thus, there must be some people who enter the kingdom in non-glorified bodies. But, everyone who is raptured is glorified. So, if the rapture occurs posttribulationally, it seems that no one is left to enter the millennial kingdom in a nonglorified body.
Third, given the context of the marriage supper of the lamb as heaven (Rev 19:1-10), followed by the second advent at the end of the tribulation, and given semitic customs surrounding marriage which John most likely would have had in mind as he wrote Revelation 19, it appears that the Church must be in heaven for this event somewhat prior to the end of the tribulation. But, how is one to explain the Church's presence in heaven prior to the second advent?
Finally, Paul states that all believers must stand before the judgment seat of Christ. At that time our works will be evaluated by Christ and rewarded. But, when is that event most likely to occur? And Paul indicates that seat is in Heaven and the rewards ceremony in Heaven.
“But, God’s judgmental wrath is poured out during the tribulation.”
Certainly, but only if you assume that the only way that God could spare believers is by whisking them away can you claim this is an argument for a pre-trib rapture. However, we don’t need to make that assumption, because Revelation 16 tells us that the wrath is only poured out on those who took the mark of the beast, which precludes believers suffering the wrath:
“And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image.” Rev. 16:2
The rest of the chapter confirms this, telling us those who suffer the wrath “have shed the blood of saints and prophets” (verse 6), “blasphemed the name of God, which hath power over these plagues: and they repented not to give him glory” (verse 9) “And blasphemed the God of heaven because of their pains and their sores, and repented not of their deeds.” (verse 11), and “blasphemed God because of the plague of the hail” (verse 21), none of which are the actions of believers.
So the wrath in the tribulation is poured out on those who worship the beast and refuse to repent. God does not target people indiscriminately, as the angels confirm “Lord God Almighty, true and righteous are thy judgments” (verse 7).
“Second, as to non-glorified bodies, Scripture shows that some people will enter the millennial kingdom in natural bodies and then give birth to children (Isa 65: 20).”
Let’s look at that verse and see if your argument holds up:
“There shall be no more thence an infant of days, nor an old man that hath not filled his days: for the child shall die an hundred years old; but the sinner being an hundred years old shall be accursed.”
This is indeed speaking about a period after the tribulation, for it is preceded three verses before by this:
“For, behold, I create new heavens and a new earth: and the former shall not be remembered, nor come into mind.”
However, the verse you cite claims that “the sinner being an hundred years old shall be accursed”. If we take this verse to be a description of people in the heavenly kingdom giving birth to babies, then we would also have to conclude that sinners would be part of that kingdom as well, which is a ridiculous conclusion that contradicts a great many scriptures. Since that interpretation creates such a glaring contradiction, it cannot possibly be correct.
“Some of those children will rebel against the Lord (Rev 20:7-10).”
Those verses say nothing about the “children” of people in the kingdom, they are about Satan and “the nations which are in the four quarters of the earth, Gog, and Magog”. In the Kingdom, the glorified believers will live with Jesus in the New Jerusalem, not “the four corners of the earth”. This is confirmed because that is where Gog and Magog go to attack them in verse 9: “And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city...”
“But, how is one to explain the Church’s presence in heaven prior to the second advent?”
Quite easily, because it simply isn’t the case. Rev 19 and Rev 20 are not in sequence, they are parallel visions of some of the same events. This is easily demonstrated by noting that at the end of chapter 19, we are told:
“And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone.” (Rev 19:20)
Yet this event is also described as happening in chapter 20:
“And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever.” Rev 20:10
Since this event only happens once (they are never released from the lake of fire between the two verses), the only possible conclusion is that the chapters are parallel and not sequential.
“Finally, Paul states that all believers must stand before the judgment seat of Christ. At that time our works will be evaluated by Christ and rewarded. But, when is that event most likely to occur?”
Mostly likely at the first resurrection, which is described in Rev. 20:4-5, where the risen believers are rewarded with thrones and judgement. This happens after Satan is bound in prison for a thousand years, which is described in verse 2, so it happens after the tribulation.