The had seen all of ______ friends except Aliza and _____ at the restaurant.

The had seen all of ______ friends except Aliza and _____ at the restaurant.

Explanation
  • "Their" is the correct possessive pronoun referring to "friends."
  • "Me" is correct because it is the object of the preposition "except."

Correct sentence:
"They had seen all of their friends except Aliza and me at the restaurant."