Sorry, can't find a Caudron C.17 fighter, nor the Descamps D.17.
Regarding Green/Swanborough ,the first mentioned Descamps design is the
Descamps 27, which was designed by E.A. Descamps, when he returned to
France after the russian revolution. As the chosen winner was the Nieuport 29,
further developmnet of this type was cancelled and I couldn't find any clue for
other Descamps aircraft.
But, as I told you before, the pre-war era is, although very interesting, really not
my playground. Perhaps you should post this question in the french aeroforum?
( http://www.aerostories.org/~aeroforums/)