Obviously, Harry himself. And his best friends Ron and Hermione would surely be there. After all, they have been through so much together with Harry.
There would also be other characters like Neville. Harry might talk about how Neville grew from a shy and clumsy boy to a brave hero. Luna Lovegood could be in it too. Harry could share his experiences with her, like their time together in the Department of Mysteries. And characters like the Weasley family members, especially Ginny, who became an important part of Harry's life, would also be likely to be mentioned.
The main characters would be Harry and his kids. But other important figures from his past would be included. Neville Longbottom could be mentioned, as they were comrades in the fight against Voldemort. And Ginny, Harry's wife, might be brought up as well, as she was an important part of his later Hogwarts years and his life in general.
Hermione would likely be one of the characters. She's Harry's best friend and would probably try to find him and help him out. Ron might also be there, as he's always been by Harry's side. Dumbledore could be another character. He might be trying to keep an eye on Harry from afar, or perhaps he has a plan for Harry's new situation. Hagrid would also be a likely character. He has a soft spot for Harry and would want to make sure he's okay. And of course, the Dursleys themselves might make appearances, either to continue their mean - spirited ways or to have a change of heart.
Hermione would likely be there. She is always interested in learning, so she'd be involved in any study related to magical creatures. Ron might also be around, perhaps getting into some comical situations with the creatures. Hagrid is another obvious choice, as he has a deep love and knowledge of magical creatures.
Other characters could include his professional Quidditch teammates. There might be a tough but fair captain, a cocky star player who initially doesn't get along with Harry, and a kind - hearted newbie who looks up to Harry. Then, of course, there could be rival players from other teams. These could be the typical antagonists on the pitch, always trying to outwit Harry during the games.
Harry is the central figure for sure. Neville Longbottom could play a role. He might be one of the few who know where Harry is hiding and is trying to protect the trunk from being discovered. Hagrid could also be involved. He might bring Harry some food and supplies while he's in the trunk. And there could be some mysterious old wizard or witch who has some connection to the trunk and its magic.
Obviously, Harry Potter himself is the main character. His friends like Hermione and Ron are likely to be there. Hermione might offer her intellectual support and advice on raising the child. Ron could be there for some comical relief and also to provide a male friend's perspective. Harry's godson Teddy Lupin could also be an important character, as he might be someone Harry looks to for inspiration on raising a child without a traditional family setup.
Obviously, Harry, Hermione, and Ron would be the main characters. Hagrid could also be there, being his large and friendly self, perhaps a bit out of place in the glitzy Vegas environment. Dumbledore might make a cameo appearance, guiding them from afar or sending them some mysterious messages. Neville could tag along too, excited to explore a new place.
The main characters would be Harry and Dumbledore for sure. But it's possible that some of the other Hogwarts teachers, like McGonagall, could also be involved. She might be a witness to the confrontation, or she could be someone Harry goes to for advice before or after he tells Dumbledore off. Additionally, Snape might also play a role, as his relationship with both Harry and Dumbledore was quite complex.
Obviously, Harry would be the main character. There could also be his friends like Ron and Hermione. And perhaps some of his enemies like Draco Malfoy or other Slytherins.