I am glad we have found common ground and formulate my theory about the Flood more accurately, in order to give adaptable responses to your questions:
In the region of the five antediluvians Sumerian cities lived about 100’000 people, among them Noah and his family. All these humans were aware of God’s law, morally responsible and capable of sinning; they were all (Noah included) in need of Redemption. Except Noah and his family all were guilty of sin and perished in the Flood. Noah took in his wood vessel some of the domestic animals living in the region: the rest drowned.
Outside Sumer, and spread all over the planet, lived about 7,000,000 human beings and practically all animal species we know today. All these living beings (humans and non-humans) had no sense of law and moral responsibility, and therefore could not be guilty of sin or be in need Redemption: They were neither “ungodly” nor “godly”. Since all of them remained untouched by the Flood, the region where they lived (almost the whole planet) was equivalent to Noah’s container from the perspective of the flooding event. It is therefore fitting to say that the “Ark” referred to in Genesis had a “very large lower deck”, as large as practically the whole earth. (It seems to me that Jim Stump suggests something similar although invoking a “miracle” on the part of God).
At the End of the Flood God endowed the 7,000,000 Homo sapiens with sense of law and moral responsibility, and consequently capability to sin, just as He had done with the Homo sapiens creatures from which He created “Adam and Eve”. However, while “Adam and Eve” before the Fall were not in need of Redemption, the new human persons did need Redemption (see later) from the very beginning of their existence the same way as Noah, his family and all the human persons God creates presently every day.
On the one hand this explains why vestiges revealing sense of law appear only at times after the supposed Flood event. On the other hand it is plausible to assume law in Sumerian cities before the Flood because corresponding tablets have been found displaying Cuneiform writings, the script used thereafter to write contracts like those found in tablets at Shuruppak and law codes like those of Ur-Nammu and Hammurabi.
Undoubtedly, in the search for truth observation is the highest authority (even higher than the Bible!). So my theory should be revised if new evidence would require it. But for the time being it seems to fit rather well to the data we have, within the rather large margins of error of today’s methods for estimating how old vestiges are.
I am assuming that:
“[T]he Bible is the inspired and authoritative word of God. By the Holy Spirit it is the “living and active” means through which God speaks to the church today, bearing witness to God’s Son, Jesus, as the divine Logos, or Word of God.” [Biologos, What we Believe, 1.]
[T]he historical incarnation of Jesus Christ as fully God and fully man… the historical death and resurrection of Jesus Christ, by which we are saved and reconciled to God. [Biologos, What we Believe, 4.]
In other words, the writers of the Bible were inspired by the Word of God to write something useful for the Salvation of humans all over the world, and therefore adaptable to the conditions of all peoples of all times, certainly by means of what they were in positions to have direct knowledge of. What is more, the New Testament must be interpreted in the light of the Council of Jerusalem (49 AD), where “the Holy Spirit and leaders of the Church” proclaimed that Salvation is not only for the Jews but for all people (Acts 15:1-35).
With this perspective the natural interpretation of 2 Peter 2:5 is that it describes:
By the way, even Flavius Josephus himself, seems to endorse the interpretation that the Flood affected the whole humanity and not only "a single lineage and culture":
“Now God loved this man for his righteousness: yet he not only condemned those other men for their wickedness, but determined to destroy the whole race of mankind, and to make another race that should be pure from wickedness; and cutting short their lives, and making their years not so many as they formerly lived, but one hundred and twenty only, he turned the dry land into sea; and thus were all these men destroyed: but Noah alone was saved;”. [The Antiquities of the Jews, Chapter 3, 2.]
In any case today, on the basis of the available data, any reasonable account about the Flood has to assume that:
About 100,000 humans living around Noah became destroyed by the Flood because of their sins,
and 7,000,000 humans living far away spread all over the world remained untouched.
In view of this scenario the interesting question is:
Were the 7,000,000 living far away capable to sin YES or NO?
If YES then we have a problem because according to BioLogos it holds that they all had sinned against God [What we believe, 3.], and the explanation of the Flood as expression of God’s Justice becomes derisory.
If NO then we confirm the explanation I have proposed above. Accordingly, at the end of the Flood God endowed the 7,000,000 Homo sapiens with sense of law and moral responsibility the same way as He did when He created “Adam and Eve”.
And now we have to decide which stage these new 7,000,000 morally responsible human beings were in: The stage of
“Adam and Eve” before the Fall, i.e.: they were not in need of Redemption;
or “Adam and Eve” and their descendants after the Fall, including Noah and his family, i.e.: they were in need of Redemption.
In other words we have to answer the question:
Would it have been sound on the part of God to keep together in this world people in need of Redemption together with people who don’t need Redemption?
The answer to this question is crucial to decide whether the stage of “need of Redemption” (which all people are supposed to share) is or not linked to the Fall, that is the first sin of human history (which is not necessarily the same as the sin of the first human person).
I would be thankful for your opinion about this.
Meanwhile I prepare responses to your questions about the interesting video “There was no first human” and “immortal souls”.