Thank you, I try.
You are. There's nothing in the passage to suggest that ordinary human sight from a mountain could see "all the kingdoms of the Earth." Quite the contrary, in fact: if you could just see them, they wouldn't need to be shown.
Now you are grasping at straws. The point of climbing an object is to extend one's range of view. Now you are trying to put something into the scriptures that is not warranted.
It depends upon where one lives. In Greece, yes, but even Homer was a Flat Earth believer, and he was 2nd century BCE. It appears that the writers of the Old Testament were Flat Earth believers as well.
There was Lactantius. Anyone else that you can give an actual quote for?
How about Saint Augustine:
"But as to the fable that there are Antipodes, that is to say, men on the opposite side of the Earth, where the sun rises when it sets to us, men who walk with their feet opposite ours that is on no ground credible. And, indeed, it is not affirmed that this has been learned by historical knowledge, but by scientific conjecture, on the ground that the Earth is suspended within the concavity of the sky, and that it has as much room on the one side of it as on the other: hence they say that the part that is beneath must also be inhabited. But they do not remark that, although it be supposed or scientifically demonstrated that the world is of a round and spherical form, yet it does not follow that the other side of the Earth is bare of water; nor even, though it be bare, does it immediately follow that it is peopled. For Scripture, which proves the truth of its historical statements by the accomplishment of its prophecies, gives no false information; and it is too absurd to say, that some men might have taken ship and traversed the whole wide ocean, and crossed from this side of the world to the other, and that thus even the inhabitants of that distant region are descended from that one first man."
I was already quite familiar with it. It's not the most reliable source.
Actually Wikipedia is quite reliable, unless you use it for gossip items and the like. There have been studies on it and though people complain about the editing that anyone can do it turns out the more an article is edited the more reliable it is. Do you need links?