Of course!Did Noah and his immediate family know about God's sons having sex with "the daughters of men"?
Did Noah and his immediate family somehow pass this information on to the Ancient Greeks, Romans, etc?
You don’t think Noah understood why Jehovah needed to clear the Earth of violence?
Even his GG-Father Enoch, in his day, saw how bad things were.
The appearance of men stronger than others, inciting violence by taking women “all whom they chose”....you don’t think that would be noticeable?
These events left an impression in their minds...of course they passed this information on to their descendants!
These other questions, about ‘God having sex’, I’m not even going to dignify with a response.
The answer to most of your other questions, relates to God’s gift of Free Will bestowed to His sentient, intelligent creatures.
It doesn’t make God an incompetent Creator...it just highlights that God respects our privacy, and would like us to honor Him willingly, not because we’re programmed to.
You are a fine example of a person displaying Free Will, by expressing your anti-God sentiments.