The sentences that contain correctly punctuated nonrestrictive modifiers are:
- My brother, John, is my favorite of all my brothers.
- My oldest sister, Maria, is a pilot.
- My two best friends, Tory and Monica, met me at the movies.
- Bulldogs, which I love, are the cutest!
The sentence "The book, Robinson Crusoe, is a classic." is not correctly punctuated, as "Robinson Crusoe" is essential to the sentence and should not be set off by commas.