Wow this is great stuff! You're absolutely right though, I'm stuck on "then cometh the night of darkness wherein there can be no labor preformed." What does that mean? Verses 34 and 35 make all the sense in the world to me: If we procrastinate, our spirit will be conditioned to wickedness and Satan will have tremendous power over us.
I also recognize that if someone were to knowingly not keep their covenants in this life and then somehow turn it around in the spirit world, they could obtain the terrestrial kingdom at best (D+C 76:74, Joseph Fielding Smith in Answers to Gospel Questions, Vol. 4).
So, it the spirit world, the wicked who had the gospel and knowingly rebelled CAN repent, but can only go to the terrestrial kingdom. But what is the reason that the celestial kingdom is ABSOLUTELY closed to them? Yes, it will be very very hard for them to repent and it's very unlikely that they will, however, that is not saying that they CAN'T go to the celestial kingdom.
I'm guessing there is some sort of penalty for not enduring to end or maybe some opportunities to fully repent are no longer there, therefore the celestial kingdom is no longer an option. Am I making sense to anyone? :)