Now What?:
Christ himself defined the unforgivable sin - Matthew 12:31-32 - as blasphemy against the Holy Spirit and he said it would not be forgiven ever.
Within context, I see the unforgivable sin as either a denial of the Holy Spirit's power or attributing it to Satan. If we deny the power of the Holy Spirit, we deny him any access to our lives - including the power to convict us of our sin - so we effectively put ourselves outside of God's mercy (and send ourselves to hell?).
So gehenna's only going to contain those who want to be there (I think C.S. Lewis said something like that too)
Like you, I don't get how witnesses say such people won't be resurrected, Hebrews 9:27 says that man dies once and then judgement follows, nobody bypasses judgement. Wouldn't they have to be resurrected to face judgement?
ps I didn't think you were being antagonistic. It's probably the way I reply that's the problem