Q missed the performers' info, which was several pages before the song (the song is part of a long medley on the CD):

Michèle Choinière, lead vocal and piano (b. 1965)
Jeanne Begnoche, lead vocal (b. 1938)
Alberta Gagné, lead vocal (1908-1999)
Fabio Choinière, harmonica (b. 1928)
Maurice Paquette, accordion (b. 1934)
participants in soirée, antiphonal response.

Fabio is Michele's dad, and he's fabulous. I saw them play together a few times in Vermont...

The song The Orange Tree, as performed by Andre Marchand and Grey Larsen, on the album of the same name, is a variant of the "La fille de l'avocat" as well--in which the gender roles are reversed and it's a "fils d'un avocat." They simply credit it as a traditional Canadian song.