Dennis:
Wow! Great research!
Now that you've brought up other definitions, I guess it would be interesting to know (1) the last surviving Confederate soldier who served in a MS unit and who actually died in MS; (2) the last surviving Confederate soldier who served in a MS unit but who died extra-MS; and, (3) the last surviving Confederate soldier who died in MS but who served in a non-MS unit.
Yes, the MS Graves index run by fantastic MS SCV member Dan McCaskill is amazing.
And, yes, those folks at Beauvoir are amazing, too!
Thanks, again, for the research! -- Jim Huffman, Adj., Gainesville Vols, SCV Camp 373, Pearl River County, MS