I think your theology hinges delicately on the condition that the spirit of a man cannot die. This single point alone, that the spirit of man cannot die under any circumstances, if proven to be untrue, would mean that the doctrine of eternal torment is debunked.
Let's look at what the Bible says about spiritual death, then.
Genesis 2:17
17But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
1 Corinthians 15:22
22For as in Adam all die, even so in Christ shall all be made alive.
Romans 6:23
23For the wages of sin
is death; but the gift of God
is eternal life through Jesus Christ our Lord.
Ephesians 2:1
1And you
hath he quickened, who were dead in trespasses and sins
Ephesians 2:5
5Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved; )
And there's many more. Spiritual life, a born again spirit, only comes through Christ. I'm sure we agree there.