You have written that some of the Jews who are saved [during the Tribulation] will survive to populate Israel in the Millennium, and some believing Gentiles will survive to populate the Nations. Will the survivors in both groups be mortal but free from disease, accidents, and a sin-nature because of the lifting of the curse from the earth? Will the Church interact with earth dwellers during the Millennium?
Post Church believers who survive the Great Tribulation, whether Jew or Gentile will go into the Kingdom in their natural states, with a sin nature. Because of the curse being lifted disease will be rare, but not unknown, and some will most likely live through the entire millennium. They’ll have offspring with long life spans as well, but just as it is with believing parents today, some of their children will not accept the pardon that was purchased for them at the cross.
Those who reject the Lord will die much sooner, some living less than 100 years. (Isaiah 65:20) It will be the survivors among these children and theirs after them who will rebel at the end of the 1000 years when Satan is released. They’ll rebel against the Lord’s rule, wanting Satan to be their King instead.
I believe that the Church will be able to visit Earth regularly, but no one from Earth will be allowed into the New Jerusalem. (Rev. 21:27) The purpose for visiting could be to see friends and family, or to conduct Kingdom business, or just for pleasure.