I just heard back from MSC. Wow, that was quick.
Good day,
In response to your email, all passengers in the same cabin must have the drink package. As long as the party you are traveling with are not in the same cabin than they do not need to purchase a drink package and you may add them as your travel with to be seated together in the main dining room.
We look forward to welcoming you on board.
Kind regards,
MSC Existing reservations