Possibly, but I have learned that Feldstein is a very common name in that region of Russia. I don't know why since I would think that Feldstein originated in Germany.
Do you know what cemetary in Baltimore they are buried? I found a Lina Feldstein who lived next-door to my grandparents in 1910 on Lumbard St. However I would have thought they would have beeen buried in the same cemetary if related, but was unable to find her.