The main characters are often the children of the original Harry Potter characters. For example, Albus Severus Potter, James Potter, and Lily Potter. Also, Scorpius Malfoy is usually a central character as he is part of the new generation at Hogwarts.
The children of Harry, Ron, and Hermione would likely be main characters. For instance, Harry's son could inherit his father's courage and be at the center of a new mystery. He might have to deal with the high expectations placed on him because of his father's legacy.
Hermione Granger would be a likely main character. She has always been a central figure. Maybe she's working on some revolutionary magical research or is involved in political reforms in the wizarding world. Her relationship with Ron and their family life could also be part of the story.
Most likely the children of the main characters from the original series. Like James, Albus, and Lily Potter. Also, the kids of Ron and Hermione, like Rose and Hugo.
Newly discovered magical families could rise to prominence. These families might have been in hiding or just not known before, but now they play a crucial role in the wizarding world of 1000 years later. Their members could be the main characters, bringing in fresh perspectives and magical abilities that were previously unheard of.
Hermione, on the other hand, would likely have a more critical view. She'd analyze the fanfictions for their accuracy in terms of magic lore and Hogwarts traditions. If there were any inaccuracies, she'd be quite perturbed. However, she might also appreciate the creativity that goes into some of the well - written ones that add new dimensions to their magical world.
The professors at Hogwarts would have different reactions. Professor Snape might be secretly intrigued by this new and strange creature while outwardly showing disdain. Professor McGonagall would be concerned for the safety of the students and would start organizing protection spells around the school. Hagrid, being the lover of strange creatures, might try to approach it in a friendly way at first, until he realizes how dangerous it is.
Obviously, the children of the original characters like James, Albus, and Lily Potter. They are likely to be at the center of many stories as they navigate Hogwarts life. Also, Scorpius Malfoy as he is the son of Draco Malfoy and his story could be intertwined with the Potters.
The Weasley family would have different responses. Mrs. Weasley would be motherly and concerned about this strange new person. Fred and George would see her as a source of new ideas for their pranks and inventions. Ginny would look up to her as a strong female figure, much like she does with Hermione. And all of them together would gradually get used to having Powergirl around, and they would all grow from the experience of interacting with someone from a completely different world.