Perhaps the travel agent is a bit of a troublemaker. Instead of suggesting normal wizarding travel destinations, they might try to persuade Harry to visit some off - limit or even illegal magical places. They could tell him about a secret portal to a dimension where dark magic is still being practiced freely, which of course, Harry would have to resist.
He could be shocked. Maybe there are some fanfictions that take a very dark turn or have unexpected pairings that he never thought of. He'd probably need some time to process such strange ideas. And he might also be curious to see how far the creativity of the fans can go. He might even get some new ideas about his own life from reading some of the more imaginative fanfictions.
Well, in fanfiction, Neville Longbottom could be one of the visitors. He and Harry could exchange gardening tips as they explore the manor's gardens. Additionally, Dumbledore's portrait might be magically transported to Potter Manor, and he could offer his wisdom and guidance to Harry as he lives in the manor. And of course, Hagrid might come with some magical creatures to show Harry, adding more excitement to the manor.
Because it can rewrite the story. Fanfiction allows authors to take the basic setting of Harry going to Gringotts and turn it into something completely different. For instance, they can make it so that instead of just retrieving money, he is on a quest to find a magical key that unlocks a powerful spell.
The headmaster might be a bit surprised at first. He would likely respect Harry's opinion, though. He has always valued Harry's thoughts and feelings. He may start to think about the implications of fanfiction on the wizarding community and how it might affect the students and the overall perception of Hogwarts.
He might be very sad at first. Harry has always valued his friends, so being forgotten by them would be a huge blow.
As time goes on, Harry could start to explore what it means to 'please' Sirius. He might recall their past relationship, the things Sirius likes and dislikes, and try to use that knowledge to his advantage. He may also feel a sense of loyalty towards Sirius that, despite the odd circumstances, makes him more accepting of the situation. For example, he might remember Sirius' love for adventure and try to engage in some magical adventures with him in a way that 'pleases' him.
He might visit the goblins to retrieve a family heirloom. It could be something that was lost or stolen and the goblins are the ones who know its whereabouts.
The characters in Harry Potter might be a bit shocked at first. Hermione would probably be very curious about Supergirl's powers and how they work. Ron might be a bit jealous at first but would eventually come around. Dumbledore, if he were still alive, would likely see it as an opportunity for the wizarding world to expand its horizons. In the Supergirl world, Kara's friends like Alex would be protective at first but would see Harry's good heart. J'onn J'onzz would be intrigued by the magic and how it could be used in their fight against evil.
Well, the Weasley family would have a mixed reaction. Molly Weasley would be concerned about how this new relationship would affect Harry and whether Medea was a suitable partner. Ginny might be a bit jealous at first but then come to accept it. In the Hogwarts faculty, Professor McGonagall would be very strict in her assessment. She would want to ensure that Medea adhered to the rules and ethics of the wizarding world. The other houses, like Hufflepuff, might be more accepting overall, seeing it as a way to bring more diversity to the magical community. Slytherins, on the other hand, would be divided. Some would see it as an opportunity to gain an advantage through this new connection, while others would oppose it out of pure prejudice.
Hermione would probably be very curious at first. She'd want to learn all about Blackfire's culture and magical abilities. Ron might be a bit more skeptical, worried that Harry was getting involved with someone from a very different background. Dumbledore, if he were still alive, would likely be very accepting and see it as a way to promote greater unity among different magical groups. The Malfoys would most likely look down on it, seeing it as Harry once again defying the traditional pure - blood norms.