If you plan meals located inside the parks, then those using parkhopper tickets have to redeem a day in their park ticket to go in for a meal, obviously.
If you just mean, can you all get the dining plan, then yes - it is based on room occupancy, they assume you have valid park admission if you are booking inside the theme parks.
For example, 4 people in the room, 2 have AP, 2 have regular ticket or hopper, the person who has the room reserved can get the dining plan for 4 people.
You don't have to have park admission if you plan to eat at the resorts or Disney Springs (i.e. outside of the theme parks, Like Sanaa, Cali Grill, 'Ohana, etc.).