There could also be some of the more minor characters like Ace the Bat - hound. He might be lying at the feet of the family members during dinner, adding a touch of domesticity. And sometimes, characters from other related storylines like Huntress or Black Canary might be invited over, creating an interesting dynamic with the regular Bat - family members.
Obviously, Batman himself. He is the central figure of the family. Then there's Alfred, who is like the family's butler and caretaker. He would be the one preparing the dinner. Robin, whether it's Dick Grayson, Jason Todd, or any of the other Robins, would often be present. Batgirl could also be there, adding a female presence to the group.
Oracle, Barbara Gordon, might also make an appearance. She could be providing some intel during dinner through her computer skills, even if she's not physically at the table. And of course, Nightwing, who has a close relationship with Batman and the rest of the family. He would bring his own charm and stories to the dinner table.