"This article doesn’t mention the fact that some of the older fossilized remains, like the Kennewick man, do not match the “native American” lines. You would think that remains that were found in Washington state would be more likely to match those that came across a northern land bridge if it was the only path of migration." Yes, the skeletons/skulls are so old we may never get DNA from them.
Vintage Skulls
Spirit Cave Man is the oldest mummy ever found in the Americas and is older than Kennewick Man. The Indians won't allow DNA testing and even want to destroy it by burying it.
The problem is that farther you go back to many Honkies and Brothers start showing up. People breed true but they also breed out, there is an urge in humans to expand the local gene pool, Eskimos, Abos and wife swapping for example.
I think that the next 20 years will be interesting.