Who are they, and where have they come from?

[Hazelelponi]

Yes good advice

My focus has been showing that the great tribulation is on the church and the wrath of God is on the unsaved.

I have enjoyed your points.

 

[Paul]

Rev 16:16 seems to put a time stamp on it.. 16And they assembled them at the place that in Hebrew is called Armageddon....

Do you see this as pre-1000 year reign or post-1000 year reign?

That day is the start of the 1000 years. Jesus ends all tribulation at His 2nd coming at the completion of the bowl judgments.
The 1000 years begins at the resurrection on the last day.
Revelation 20:4

Just as Paul wrote 2thess2
And then the lawless one will be revealed, whom the Lord Jesus will overthrow with the breath of his mouth and destroy by the splendor of his coming