I'm not sure anyone uses full leather toe stiffners? Not in ready-to-wear anyway.
They use both French and Italian tanneries I believe. I mean, it's like any other business, you usually don't trade with just one partner. Sometimes you need to source similar parts from various different suppliers just because of supply and demand or other business reasons.
The first question is a common one, and I can see the reason for it but for the second one - people has to realise that shoemakers can change suppliers for theirs soles, and even uppers, and any other part at any given time and it's very seldom they actually inform clients or even their retailers about this. It happens all the time with every maker we carry. I'm not saying it's not a good question because obviously curiosity is good - but the answer is "it most likely changes now and again".