In Matthew 13:30 the reapers are told to gather first the tares and bind them separate from the wheat and in Matthew 25:32 it says He will separate them one from another. It could make sense to say at the GWT the sheep and goats are separated by Him, then the reapers first bind the tares/goats, and finally the wheat/sheep inherit the kingdom/barn.
But Matthew 13:30 happens at the time of the harvest, not after the earth has been harvested.
Did you read Jesus's explanation of that parable in Matthew 13:36-43? If not, you should. It makes it much easier to understand the parable. Jesus said that "the harvest" represents "the end of the age" (Matthew 13:39). The KJV says "the end of the world" but the words "age" and "world" are translated from the Greek word "aion" and the word "age" better reflects the meaning of the word. Translating it as "world" just makes it potentially confusing because people might think it's referring to the end of the "cosmos" instead of the end of the "aion".
Anyway, after Jesus explains what each term in the parable represents (field = world/cosmos, harvest = end of the age, reapers = angels, etc.) in Matthew 13:36-39, He then said this:
Matthew 13:40
As therefore the tares are gathered and burned in the fire; so shall it be in the end of this world. 41
The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity; 42
And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth.
This is very similar to what we see described in Matthew 25:31-46. The wheat are separated from the tares. The sheep are separated from the goats. Clearly the same event, in my opinion. Especially when you see the description of the tares being cast "into a furnace of fire".
If that doesn't remind you of the following, I don't know what to tell you:
Matthew 25:41 Then shall he say also unto them on the left hand,
Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:
It seems that if Matthew 13:30, Matthew 25:31-46, and Revelation 14:14-20 all have to harmonize to one single event then something won’t line up.
I agree. But, Revelation 14:14-20 is not the same event as Matthew 13:30 and Matthew 25:31-46, as I have shown. Revelation 14:14-20 is not a reference to the judgment, but rather to what will happen to believers and unbelievers immediately after Jesus descends from heaven. As Paul taught in 1 Thess 4:14-17, the dead in Christ will be resurrected at that point and they, along with those who are alive and remain, will be caught up to meet Christ in the air. That is portrayed symbolically by Revelation 14:14-16. Then, living unbelievers will all be physically killed, as 1 Thess 5:2-3 indicates (cross reference with 2 Peter 3:10-12). That is what is portrayed symbolically in Revelation 14:17-20.
So would this be the sequence of events?
1 the dead in Christ are raised up to meet in the air
2 the dead who are not in Christ are raised
3 the GWT where He places the wheat/sheep on His right hand and the tares/goats on His left
4 the harvest takes place and the tares/goats are bound first by the reapers, then the wheat/sheep inherit the kingdom/barn
This sequence doesn’t seem to make sense, since no place is found for heaven and earth at the GWT in Revelation 20:11, yet a non existent earth would get harvested.
I believe you are taking the term "the harvest" too literally. Jesus said "the harvest" represents the end of the age. Don't read any more into it than that. When He talks about things happening "in the time of harvest" He's simply talking about what will happen at the end of the age.
So, in my view, this will be the sequence of events on the day of Christ's second coming (if 1 Cor 15:51-52 is any indication, this all will happen quickly in succession):
1. Jesus, His angels, and the souls of the dead in Christ will descend from heaven (1 Thess 4:14, 2 Thess 1:7, Matthew 24:30-31, Mark 13:26-27, Rev 19:11-21) with the sound of the last trumpet (trumpet of God, seventh trumpet of Revelation).
2. What happens first after that is that the dead in Christ are resurrected from the dead (1 Thess 4:16, 1 Cor 15:22-23, 1 Cor 15:52).
3. All believers from all-time, including the resurrected dead in Christ and those who are alive and remain, have their bodies changed to be incorruptible and immortal (1 Cor 15:50-54). The souls of the dead in Christ unite with their changed bodies at the same time.
4. The resurrected dead in Christ and those who are alive and remain are gathered and caught up together to meet the Lord in the air (1 Thess 4:17, Matthew 24:31, Mark 13:27).
5. Living unbelievers are all physically killed as the heavens and earth are burned up (1 Thess 5:2-3, 2 Peter 3:10-12, Matt 24:35-39, Rev 14:17-20, Rev 19:17-18, Rev 20:9).
6. Dead unbelievers are resurrected (Daniel 12:2, John 5:28-29).
7. The saved and lost are all gathered and separated (Matthew 13:30, Matthew 25:31-33) with the sheep (same people as the wheat) being put on the right hand of Jesus when He is on the throne and the goats (same as the tares) being put on the left.
8. The sheep (saved) inherit "eternal life" in the kingdom prepared for them from the foundation of the world (Matthew 25:34) on the new earth (2 Peter 3:13, Rev 21:1-7).
9. The goats (unsaved/lost) are cast into "everlasting fire prepared for the devil and his angels" (Matt 25:41) for "everlasting punishment" (Matt 25:46) that will result in "everlasting destruction from the presence of the Lord, and from the glory of his power" (2 Thess 1:9). That "everlasting fire" is also known as "the furnace of fire" (Matt 13:43,50) and "the lake of fire" (Revelation 20:15).