I don't have any more information to give you on these Mecklenburg Civil War veterans (birth, death or burial locations). I did have a different date and location on James H. Alexander. James H. Alexander born September 1836 killed on May 3, 1863 in Civil War battle in Kentucky. I can't remember where I got this info, sorry.
I'm in the process of making a "Alexander Veteran" web page that list the Alexander veterans of all the American wars. I would appreciate a copy of your list after you have completed it so that I can correct my veteran web page.