Searching further for Louis Lagaurnadie, I did find this discussion in an obscure posting forum (Axis History Foundation) ...
How about the ww1 Veterans that are still lives today at France?
How many of them are still alive?
Wikipedia says seven, of which one served in the Italian army (and another served in both the French and Italian armies; it says he was in the Foreign Legion, so he may be the oldest Legionaire), one isn't officially counted because he fought in Syria, and one served for less than three month. The article also cites a potential eighth, who remained unidentified and so can't be verified.
A Wikipedia link was cited but doesn't lead to an article...
And he was answered here:
Datas seem corrects only 3 now officially with the death of René Riffaud last 15th january :
Louis de Cazenave born in 1897
Lazare Ponticelli born in 1897 in Italy, French citizen now, served in the French Army during the Great War
Jean Grelaud born in 1898
Justin Tuveri born in 1898 French citizen, was an Italian soldier during the First World War so should be counted with Italians Veterans
Tried several variations for a Wikipedia search, and was able to locate this article... but it does not indicate location information (other than a given country) for the WW I Veterans cited... still some interesting personal information. Their birthdays hare shown, but nothing else is listed for Grelaud. There is one note for Lagaurnadie.
This article does list (in the German section) the cities of residence for Kaiser (Streufdorf/Thuringia) and Solveen (Darmstadt/Hessen). Christmann and Kastner are also listed, without any further notes.
Will try a few more possible resources but thought I would report these finds to date.