MZTV 1651: The State of the Nations During the Millennium and on the New Earth

There will be many living during the Millennium (the thousand years during which Israel reigns on the earth) and upon the New Earth who will not be immortals. How will they stay alive? WILL they stay alive? And what is the purpose of the "log of life" in the New Jerusalem? And why does the Concordant Version translate this "log of life" rather that "tree of life"?
And what proof do I have that we, post snatching away, will help our loved ones during the Tribulation?

So many questions. And—as is my habit—so many answers.