A few comments.
How did God with holy spirit impregnate Mary?
Obviously we do not know the specifics. This much we do know. The Holy Spirit is God. God is our Creator. God has the power to create life. So, apparently, either God created and placed in Mary's womb a human sperm cell which united with her own egg cell to produce the baby Jesus, or God created and placed in Mary's womb a fully fertilized human egg cell which grew to become the baby Jesus. This was able to take place because God, a.k.a. the Holy Spirit, is able to create life. There is nothing in Scripture which indicates that angels have that power.
The rest is nice but there was no godly line of [Seth or] anything yet. Also considering there was no hebrew religion to be had to mix with this makes no sense.
Gen. 4:26 - "Seth had a son, and he named him Enosh. At that time men began to call on the name of the Lord."
Face it God hated mankind all of them except Noah and he tolerated Noah's family. He did not even give the rest of mankind a warning to build their own boats.
The Flood of Noah's day was a local flood. God brought judgment only upon a land of people who were all descended from worshippers of the true God and who had all been given a strong warning to return to the worship of that God. That warning was given to them by "Noah, a preacher of righteousness." (2 Pet. 2:5) The judgment God brought upon the land of Noah did not affect "the rest of mankind" who lived outside of Noah's land. Thus "the rest of mankind" needed and received no "warning to build their own boats."