Obviously, Petunia is one of the key characters. Then there's Harry, as it's about her meeting his family. And members of Harry's family like his parents, James and Lily, would also be important even if they might be in memories or magical apparitions.
The key characters in 'Petunia Meets Harry's Family' fanfiction are Petunia, of course. Harry is another central figure. Additionally, the Weasleys could be involved as they are an important part of Harry's extended family. Their presence could add more color to the story as Petunia experiences the wizarding family culture through them. Also, Dumbledore might make an appearance as he has always been connected to Harry and his family's story, and could potentially be the one to facilitate the meeting between Petunia and Harry's family in some way.
Well, in such a fanfiction, Petunia might finally come to terms with Harry's wizarding world. Maybe she starts to see the magic in a new light and reconciles with the fact that her sister was a witch.
Well, obviously Petunia is one of the main characters. She is Lily's sister and has a complex relationship with the wizarding world. Then there are the Marauders - James Potter, Sirius Black, Remus Lupin and Peter Pettigrew. Each of them has their own distinct personality. James is the confident and sometimes arrogant one. Sirius is the rebellious and charming one. Remus is the more reserved and intelligent one, and Peter is the rather meek and follower - type among them.
Well, Petunia can be really well - written. If the author delves into her insecurities and jealousy towards Lily, and then shows how she reacts to James, it can create a very complex and interesting character. For example, a good fanfiction might show Petunia's internal struggle when she sees James' charm and popularity.
Obviously, Commissioner Gordon and the Bat family members. The Bat family includes Batman, Robin, and probably Batgirl.
Well, it depends on the specific fanfiction. Some fanfic authors like to play around with the relationships and concepts in the Harry Potter universe. So it's possible that in certain fanfictions, Petunia is Harry's pet. However, in the canon story, Petunia has a very different role as Harry's rather unfriendly aunt who begrudgingly takes him in. But fanfiction allows for all kinds of creative interpretations.
Will's family members are also important. His parents, for example, would be key characters. They are the ones who will form an opinion of Nico. Siblings, if Will has any, could also be important. They might be curious about Nico, or they could be a bit protective of Will and initially be a bit wary of Nico. There could also be other relatives that are part of the family dynamic in the fanfiction.
Obviously, Petunia in the form of reborn Harry would be the main character. Vernon and Dudley Dursley would also be important as they are part of the family. And we can't forget about the wizarding world characters like Dumbledore. He would surely notice some changes in Petunia and might start to investigate. Also, there's a good chance that Hagrid would be involved in some way, perhaps bringing some news or event that would set the story in motion for Petunia!Harry.
There could also be other characters from the original Harry Potter series popping up. For instance, Dudley might be in there, and his relationship with both Harry and Aunt Petunia could be explored further in the context of this fanfiction. And of course, depending on the direction of the story, some of Harry's friends from Hogwarts like Ron or Hermione could make an appearance, especially if the story involves the wizarding world interfering with Aunt Petunia's life.
Obviously, Harry and Hermione will be there. Hermione's parents are likely to appear as they are her family. Maybe her grandparents or other relatives could also be in the story. And if Hermione has any pets, they might be there too, like a cat perhaps.
The main characters would be Garcia and Morgan's family members. Garcia is an important character from the show, and Morgan's family includes his parents, siblings, and maybe other relatives.