The veterans of the CSA are, by act of Congress, veterans of the United States of America
This is incorrect. They were veterans of the Civil War. They were never granted status as Veterans of the United States Armed Services. A couple of thousand of their widows were granted a federal pension equal to that of a Union veteran widow. They were give head stones at no cost by the VA, but the head stones are different than those provided to Veterans of the Armed Forces of the United States.
They are "Civil War Veterans" by act of Congress. The rest still applies.