I am also researching the Coupal family in Lebret Saskatchewan. My family lived in Sedley Saskatchewan. I believe Camille Coupal, who was the first Coupal in Sedley in 1903, also lived in Lebret or Fort Qu'apelle. My great Grandfather was Dosithe Coupal (1850-1922)who was born in St. Philippe, Laprairie, Quebec.
I am also trying to trace his connection to Sixte Coupal who is buried in the Lebret cemetary.If you are still interested, I would love to hear from you.