The Ninevites were warned, is it possible that God knew they would repent and turn around if warned? Yes, thus the warning.
Pure speculation. Once you start trying to make your case with speculation, you can just make up anything. Best to stick the written word and get torn up over that things you just make up.
In the time of the OT this was the way it was. Whether the accounts are literal or allegorical matters little, either way we learn something about God.
Correct. We have learned that God killed more people than anything else, felt that slaughting women and children and cutting open the stomachs of pregnant women was a good idea. We learn that the Israelites acted worse than the peoples around them. By inference, we learn association with God makes people worse and kills the neighbohood.
There is only One who can guarantee that each man and woman and child has a hope for a better life and though we may not understand Him, or think His ways wrong, it is a hard truth that it is only through God that all peoples and individuals can have a hope for a better life, a life worth living.
That's right, you too can have a better life of "Submit or die."
Killing the shit out of EVERY LAST M#therF%cker in the room seems to be a common thing with God.