A few questions/points:
What does that mean, exactly?
This is in no way a feature of GAE. In fact, the claim is that almost everyone who was alive and had children at the time of A&E would also be ancestral to everyone in the world by the time of Christ.
Finally, what if anything does all that have to do with Noah and the Flood? Who, in this view, died in the Flood? Who survived? How does it mesh with the biblical story?