Correct he didn't live in the Old Testament but he knew Jewish traditionPaul does not live in the Old Testament. You can imagine all you want, what he meant, but it's clear that the 3rd heaven means something completely different than what was viewed in the Old Testament.
I suspect that neither you nor your theology knows what the tree of life or the paradise of God is. Neither are in heaven.
Again, it doesn't appear that you know anything about the tree of life or its location. Tell me, how does the leaves of the tree "heal the nations" if there it's in heaven?
yep. Not in heaven.