Here's what a glass artist friend of mine had to say:
"I'm leaning toward another maker. I agree with Kevin, that the shape of the eyes and mouth are of a cartoon appearence, and Franchini seemed to steer clear of that "cartoon" look. As a murrine maker I can say that you would most likely build one face for several attempts, Franchini's face's are from the same pull, each of the illustrated slices have different faces, which would mean Franchini would have to pull three faces to have made all the slices. ... I almost wonder if these could have been made by the same unknown maker that made so many scent bottles with the gondola, the Rialto bridge and the many faces. If so I think this would lead me to believe that this maker was trying to "copy" Franchini murrini, and maybe Franchini's work had seen a surge in popularity and value to create this market for "fakes". It's really hard to say, and I'm surprised anyone would spend so much time making another persons artwork, without trying to greatly improve upon it."