You just love Rev. 20. You're putting all your eggs into a very unreliable basket.2 Peter 2:20. But, look at the entire context. You'll see it isn't really saying what you think it's saying:
2Pe 2:1 But false prophets also arose among the people, just as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Master who bought them, bringing upon themselves swift destruction. (ESV)
The whole chapter is about false prophets. It stands to reason then, that "the knowledge of our Lord and Savior Jesus Christ" isn't referring to salvation. It can't be--it's speaking of false prophets "who will secretly bring in destructive heresies, even denying the Master who bought them, bringing upon themselves swift destruction."
Such people are not saved and so, yes, will be among all the unsaved, all the unbelievers, who will be resurrected "unto the resurrection of damnation." Just as Rev 20:11-15 shows. There is absolutely no basis for believing that Rev 20:11-15 only refers to those who were once Christian.
Can you tell me why Rev. 20:5 says that the resurrection that comes at the end of the Millennium, that begins when Christ returns per Pre-Mil doctrine, is the First Resurrection when it's clearly a later resurrection than the one in John 5? The "rest of the dead" won't live again until that time 1,000 years later and you accept that it is the First Resurrection?
Not good. Not good at all.