Evidence suggests most of the 34 people are locals, starting with the fact that some photos are credited to Henry Baumgarten, a 19th century Charlotte photographer and leader in the local Jewish community. Baumgarten died in 1918.
You can read more in an article by Mark Price in the Charlotte Observer at http://goo.gl/4Bcz1. The article also contains contact information for the Levine Museum of the New South.
My thanks to newsletter reader June Lioret for telling me about this interesting mystery.