St. Mary's Choir in Akron, Ohio sang the Labat's Regina Coeli in the 1980s. It has appeared in other hymn books including St. Basil's. Nicola Montani editor of the Catholic Choirmaster in the April 1919 issue did not give it rave reviews and considered it "Sacred dance music." But I don't think that is saying a lot. He was being very critical of one of the most widely used hymnals of the day and that was the St. Basil's Hymnal.

There is a nice youTube video https://www.youtube.com/watch?v=czjfUvN_WNA
There is also a 4 part version on the CPDL https://www.cpdl.org/wiki/index.php/Regina_coeli_(G)_(Anonymous)

M. Labat also compose the music for Snow and Rain Have Vanished - De La Salle 1913
There is an artical in THE MUSIC WORLD January issue 1861. The article is about Music and Theaters in Paris and states that he was "formerly Professor of History at the Academy of Music" presumably in Paris. In another periodical THE ATHENAEUM November 24, 1860, he is introduced as "M. Labat, a new tenor, is about to adventure at the Grand Opera of Paris, in the arduous part of Eleazor in 'La Juive," A few months later in January 1861, he listed as "ex-Professor of Philosophy, M. Labat, who for two years past has been training for the Grand Opera, at Paris, on the strength of a remarkable tenor voice, made his first appearance in 'La Juive.' He was somewhat a historian on music. There is a mention of him in the Encyclopedia Britannica Vol. 3, 1878.

I've compiled thes little factoids in a txt file on this composer. I have many such files on music composers and authors. Hopefully this will give you a good start on his background.

Thank you Don. This is very helpful.