In the picture of the train at the Ponts Noirs at Treguier, the loco is a Blanc Misseron not a Corpet. You can tell by the deeper bufferbeam (the BM locos had tramway skirts), and the different cab profile with much squarer corners. These details come from Les Petits Trains de Jadis by Henri Domengie - the absolute bible for French narrow gauge fans, unfortunately no longer in print.
From the same source: the train at Mont St Michel is standard gauge (Compagnie des Tramways Normands) - the give-aways are the buffers and flatter cab roof.
The locos with balloon stacks ran on the Tramway de St Romain-de-Calbosc, which was only 4kms long. The line was originally provided with steam tramcars, these were underpowered and soon laid aside in favour of three 10 ton Corpets. Domengie says they all had balloon stacks to contain the cinders, but these were later altered to the more normal chimney.