There could be some antagonists as well. Maybe some dark wizards who were enemies of the Potter family in the past and are still lurking around the house, trying to stop Harry from taking full control. There might also be some Ministry of Magic officials who are interested in the House of Potter for various reasons, such as the possible presence of powerful magic items. And Neville Longbottom could also be involved, as he was a key figure in the fight against Voldemort and could be there to support Harry in this new adventure.
Obviously, Harry Potter himself would be the central character. His friends like Hermione and Ron would probably also play important roles. They might be his advisors or the ones helping him carry out his plans. Dumbledore could also be a significant figure, even if only in spirit or through flashbacks, guiding Harry's actions as he tries to take over the world.
In this fanfiction, it could be that Harry takes over the House of Potter to restore its former glory. He might have to deal with dark forces that have been lurking around the property, and he uses his skills and the help of his friends to cleanse it. Maybe he uncovers a plot against the wizarding world that was somehow connected to his family's house, and he has to prevent it from coming to fruition.
Hermione would likely be there. She's Harry's best friend and would not let him be in juvie alone. She'd probably be trying to find a way to get him out legally, researching all the laws and loopholes. Ron might also show up, being another one of Harry's closest friends. He could be the more impulsive one, thinking about breaking Harry out rather than going through the proper channels. Dumbledore might also be involved in some way. He has always been a guiding figure for Harry, so he could be working behind the scenes to ensure Harry's safety and find a way to clear his name.
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.
Obviously, Harry Potter himself would be the main character. Since it's about him taking Newts early, he would be at the center of the story. Hermione might also play a significant role as she often helps Harry with his studies and could be guiding him through the early Newt preparations.
His friends like Ron and Hermione would surely support him. They have been through a lot together, and they believe in Harry's leadership. Also, the Weasley family in general would be behind him. They have always been on Harry's side in his battles against the dark forces.
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.
Obviously, Harry Potter himself. He's the main character and the one who can talk to snakes. Hermione might also show up. She's always curious about new things and would probably be interested in Harry's snake - talking adventure at the zoo. Ron could be there too, perhaps being a bit scared of the snakes at first but still supporting Harry.