He could meet other young wizards and witches who are also on vacation. They might be from different parts of the wizarding world. For instance, a group of wizards from a far - off land with unique magical traditions.
Well, he might visit some magical places that are not shown in the original books. For example, a hidden beach with mermaids and magical sea creatures. He could also meet some new characters who are on vacation as well, and they could have all kinds of adventures together, like exploring a mysterious forest filled with enchanted plants.
Harry might encounter some magical nomads. These are wizards and witches who don't settle in one place but travel around the wizarding world. They could introduce Harry to different cultures within the wizarding community and show him some unique magic that he has never seen before.
Well, Harry could be really confused at first. Ouran is a very different world from Hogwarts. He might be shocked by the opulence of Ouran Academy and the strange club system there. Maybe he'd try to find a way to fit in while still being true to his wizard self.
One common theme is discovery. Harry and his friends often discover new places in the wizarding world during their vacations. Another theme is friendship. Their relationships are strengthened as they go through different adventures together. And there's also the theme of magic outside of Hogwarts. We get to see different types of magic being used in various vacation settings.
He might meet international aurors. These are highly skilled wizards from different countries who are experts in dark wizard catching. They could teach Harry some new combat spells.
He could meet Fleur Delacour's family. Since Fleur is from France, her family might be an important part of the French wizarding community that Harry interacts with.
Hermione would be a likely companion. She loves learning and exploring, so she'd be eager to go on a traveling adventure with Harry. Ron might also tag along, especially if there's a chance of food and adventure. Neville could be another option. He has grown a lot in courage and his knowledge of plants could come in handy in different magical environments. Luna Lovegood would be a very interesting companion too. Her unique perspective on magic and the world would add a lot of fun and mystery to the journey.
Harry could meet some local magical creatures that are unique to Africa. For example, there could be a magical creature similar to a hippogriff but with different characteristics. And he may also meet African witches who are experts in herbal magic, which they use to heal and protect their communities. They could teach Harry some of their techniques and knowledge.