Arthur, thank you so much for sharing your very complete files !
Just a point, if I may, about one element of the Louvre parure :I convinced the corsage brooch, added later, cannot be the missing side-element from the original diadem.
For two reasons : 1/the side-elements are of reduced size, as can be seen on those remaining on the shortenned diadem in the Louvre ; the brooch is clearly bigger. 2/the saphires of the brooch are of lesser quality (flaws and dark color) and and do not match those - much nicer - on the diadem and necklace.