The black and white picture I recently came across in the 1928 Blumenschmidt catalogue has me seriously wondering whether 'Feuerzauber' might be the true identity of "Francis Dubreuil - in commerce as".
The other photo in the Rosen-Zeitung and Journal des Roses shows a lighter red than we might usually associate with "FD-i.c.a." but the 1912 reference says it has the same colour as its seed parent 'Prince Camille de Rohan' which is generally darker. 'Feuerzauber's breeding as a Hybrid Perpetual-Hybrid China cross fits in nicely with "F.D. - i.c.a."'s indeterminate classification too. The descriptions of fragrance, velvety black sheen, continuity of flowering, height, and even the small prickles for 'Feuerzauber' seem to match to a large degree. When I look at photos of 'Prince Camille de Rohan' it certainly looks as if it could be a parent of "Francis Dubreuil - in commerce as". It starts with an 'F' too, just in case a labelling error resulted in the mixup :-)

Something to think about, anyway.