Who is “they” in Gen 11:2?

Moreover, at what point of the genealogies of Gen 10-11 did “they” make their move (11:2) and begin the city and tower (11:3-4)? Considering the longevity of the post-diluvian patriarchs, who was alive at the time? The pronoun grammatically refers back to “the whole earth” in Gen 11:1, which seems to imply all of humanity. Again, consider that it was in the day of Peleg, the great-grandson of Shem, that “the earth [was] divided” (Gen 10:25). Assuming that this means the division of mankind at the Tower of Babel, some interesting consequences fall out of the text. Noah and his named descendants through Peleg were all alive at the time of the Tower of Babel, as can be seen by comparing Gen 9:28 (“Noah lived after the flood 350 years”) with the ages assigned to his descendants in Gen 11:10-19. Indeed, Noah’s descendants from Shem through Peleg’s father, Eber, all outlived Peleg by a significant number of years; they even outlived Abraham. It is surprising that the text does not mention or report anything about these startling consequences. In any event, “they” therefore very probably means “all of humanity living,” at least, all of humanity acknowledged in the Bible.