Monique hs done a lot of work preparing these indexes. I am only a kibitzing bystander.
Since I have copies of the volumes, I will be glad to provide scans of songs of interest to you.

Songs not of French origin-
Berthier includes under folk songs some by well-known composers (e. g., Old Black Joe by Stephen Collins Foster), and others (Moby Dick), which seems to be a modern song by a French composer. Michael Row the Boat Ashore is listed as a spiritual (it is a work song) and the name is listed as Michaël. These peculiarities all seem to be related to non-French songs, and do not detract from the importance of the volumes.