How many witnesses there were is unknown. To assume the wise men were the only ones is silly. There is no reason I see yet, to assume that there were not hundreds of thousands that saw the light. Not that they all knew what it was, but word likely spread fast.
That's called "just making shit up."
The reason the wise men followed the star, was because the thing led them right to the house. No astrological sign can do that.
Well, first, it wasn't that easy. They even had to stop to ask directions, so the astrological sign is even more likely.
Aslan is not a
Tame Lion