Very attractive build. Glad you got the fork and seat binder worked out.
As to the builder, it was certainly built by Carre, under contract for the Derepas shop, which was a very common practice at the time. When I forwarded you that email from Derepas' son, I think he was a bit confused when he said his father built it. With the Carre stamping on the seatstays it certainly came from Carre's shop.