This is a partial response to the issues brought up in a reddit forum. At some point I should probably just respond to all 11 questions, but this covers a lot of it.
Could an uneducated boy
Joseph Smith was not uneducated. Regardless, most of the theories being tossed around exmo circles these days involve other co-conspirators who had been preachers (Rigdon) or educated at Dartmouth (so, Hyrum Smith, where he probably heard John Smith’s lectures). See the intro here
come up with 531 pages of ancient scripture on his own
It seems that numerous individuals have come up with far more scripture than 531 pages. Joseph’s feat was not particularly remarkable among the list of potential holy books.
that was historically accurate
A few things have been discovered which line up with expectations for the BoM. Many things do not line up.
and prophetic in nature?
I’m aware of nothing in the book that is prophetic in nature. In fact, the book is clearly the product of an early 1800s mind.
Would it be possible for that boy to understand and include ancient Hebrew literary writing styles such as idioms and Chiasmus, some of which weren’t even discovered until long after Joseph Smith was gone ?
This claim is overstated: Summarizing the best arguments against chiasmus as evidence of the BoM’s ancientness
How would Joseph Smith have been able to know so much about the Middle East, especially the Arabian Peninsula where Lehi and his family traveled? The book includes findings in that region that no one had discovered yet.
Unsubstantiated. In general, we underestimate what was known about the region in JS’s time. And, most of the trek through Saudi Arabia corresponds with events from JS’s life.
How could Joseph Smith come up with roughly 200 new names in the Book of Mormon and then have them turn out to be Semitic in nature?
Perhaps by lifting them directly or with slight modification or embellishment from the Bible, including the apocrypha?
Why are there volumes of books written by non-LDS authors stating that Christ came and visited the America’s a couple thousand years ago just like it says in 3rd Nephi? (See Example “He Walked The America’s”) How would Joseph Smith have known this when at the time no one even considered it?
Perhaps because the preacher where Oliver Cowdery lived was writing books which contained this idea? From Dale Morgan on Early Mormonism:
View of the Hebrews made much of the destruction of Jerusalem, the scattering of Israel, and its promised gathering “in the last days,” themes which are central to the Book of Mormon. Both books quoted extensively and almost exclusively from Isaiah, anticipating the literal fulfillment of Isaiahic prophecies; both conceived the American nation as the instrument by which Israel in America should be saved in the last days; and even the Book of Mormon’s conception of a ministry performed by Christ in the New World is implicit in Ethan Smith’s view of Quetzalcoatl, the dominant figure of Aztec mythology, as a “type of Christ.” (emphasis added)
If we have the stick of Judah (record of the Jews or the Bible), then where is the stick of Joseph that is referenced in Ezekiel 37:15-20? The Book of Mormon is the only explanation for this scripture.
In “This is My Doctrine”, BYU professor Charles Harrell argues against this interpretation (quoted from here):
Scholars point out that each of the sticks Ezekiel refers to is no more than a piece of wood (hence the term “stick”), on which he was to inscribe a short phrase. It doesn’t appear to have been a scroll or writing board on which a lengthy record might be kept.
… Any uncertainty regarding the intended meaning of this passage disappears in the next verse in which the people ask ‘Wilt thou not show us what thou meanest by these?’ (v.18). Ezekiel responds that the sticks represent the kingdoms of Judah and Joseph, and that the joining of the two sticks symbolizes the reuniting of the two kingdoms under one king (vv. 19-23). Many LDS scholars today concur with this contextual meaning and therefore see the traditional LDS interpretation as a “secondary,” “revealed” meaning
How could there be so many witnesses of the Book of Mormon and the plates and not one of them deny their testimony even when some of them became bitter toward Joseph Smith? With so many people involved…a hoax of this magnitude could never go uncovered. How could the Book of Mormon never contradict itself while being an extremely complex book? After all these years…someone would have found something…but no.
Most theories posit only a few co-conspirators (if any). Again, see the intro here.