The same exact thing was offered last year.

And they had the same foods as well. I tried the buche de noel at the bakery in France last year. It wasn't very good, kind of dry. I didn't really see anyone buying the special foods that were being offered.
You pay for each food individually.
You just pay as you go.
It won't affect the crowds. The same thing was offered last year and it's not a huge thing like the Food and Wine Festival. I don't think many people even noticed the special foods being offered.