Like I said, I had no supporting data on that claim. Just hearsay.
Yes, I agree with much of what they say in that article. The problem I have is that I was debating the falsifiability of the claim through genetics 10 years ago, since there is plenty of room in the BoM for Native Americans not to be genetic descendents of Laman and Lemuel.
Yes, I have seen that as well. The standard stance of the church has always been that the Native Americans are descended from the Lamanites. That does not mean it is supported by the BoM.
Let me at this point put forth my opinion on the LDS church. This is my opinion. I am not presenting facts or arguments:
The LDS Church has two things as it's foundation. Joseph Smith was a prophet of God, and The Book of Mormon is a true account. If you prove beyond a doubt that either is false, then you will break the foundation of the religion as it stands today, and the membership will fall off. Disproving them is not a matter of shooting little annoying holes in the stories, since all stories have little annoying holes. You cannot break the foundation with absence of evidence. The average membership will, however, respond to compelling contrary evidence.
Having stated that, I agree that the genetics argument is important to the debate. But I believe that LDS Church has weaseled out of things by changing their stance without having to change the BoM. As long as they can do that, they will not have any trouble with such evidence.
For example, polygamy was not directed by the BoM. Therefore, it was easy to remove. The earlier rule about blacks holding the priesthood was similarly not directed by the BoM, so was again relatively easy to change. Shoot holes in the BoM directly, not in the way it has been interpreted.