tales of mines of copper and maybe even iron mined in Minnesota

And what makes you think Amerindians were unable to mine ore? North American peoples used mostly native copper and meteoric iron, and there are numerous copper artifacts (usually plates) from Mississippian culture (they were kind of a status symbol).

"And Kennewick man looks in the reconstructed face just like Patrick Stewart the Shakespearean actor."

It should be noted that an Artist/Scientist, attempting to recreate a sculpted likeness from a skull, does not derive the likeness from the skull. The sculpted image they create is derived partly from measuring and mostly from speculation on what racial background they determine most likely matches up with the skull. In the case with Kennewick man, the sculptor chose the Ainu people of Japan as his inspiration.

So, if a person would think a point for Joseph Smith's corner could be got by projecting their own vision, of Book of Mormon origin, onto the appearance created by the Sculptor of Kennewick man, they would need to keep grasping in another direction.

"A few recent publications and documentaries have hypothesized..."

You mean a bunch of con artists and 19th century writers of Biblical fan fiction.

It turns out the unsubstantiated bullshit is unsubstantiated bullshit. Go figure.