Thank you, everyone, for your responses! I knew that I could count on Cruise Critic for information!
We will be embarking in Marseilles and doing the Western Med, so I'm expecting that every port (except Tunis?) will have new people. The many languages doesn't bother us, as we're used to that from our previous travels in Europe. We're going to Europe to experience the culture, so that's part of it. I'm surprised (but pleased) that there would be trivia!
Given the different responses on smoking, I'm guessing that it varies from cruise to cruise.
I don't mind less salty, as I can always add salt (that's why there's a shaker on the table right?). Less sugar... depends on the dessert, but I'm sure that there will be plenty to eat, so I'm not too worried.
For anyone else interested, I did find some Med menus here. Many of the dishes do look familiar from our Caribbean cruises, so I would expect the recipes to be the same. But there are definitely more seafood dishes.
https://www.alannazingano.com/videos/yacht-club-menus-on-msc-grandiosa-mar-2023