Alright, as far as the New Earth and New Heaven go this is what I got. When you die, you go to paradise (heaven) or hell, depending on obvious reasons. Since we were created (our spirits that is) in Gods image, the human spirit is eternal (or immortal so to speak). At some point, after judgment (or maybe just before?) every human spirit will be granted their perfect bodies (wether their doomed for hell or not). Then, in these perfect bodies, we will either be thrown into a lake of fire and be punished for all eternity (God made the spirit and perfect body immortal, he wont destroy you) or begin a new life on the new Earth. Earth was made for man, heaven for God and hell for Satan, although many humans will be thrown in with him to suffer forever.

Alright... Now, will there be Cannabis? It exists for a reason wether that reason be to intoxicate, I dont know. If it has a reason on the new earth, then it will be. I think God would have considered abuse of MJ when it was made but things are good in moderation... so im not sure dude.