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.
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.
One of the common tropes is the 'soul - bond' trope. In fanfiction, characters might be magically bonded at a soul level, which affects their relationship and actions. For example, Harry and Hermione could be soul - bonded, and it would change how they interact with each other and other characters. Another trope is the 'secret identity' trope. A character might have a secret identity or past that is slowly revealed throughout the fanfiction, adding drama and mystery. The 'reincarnation' trope is also seen sometimes, where a character is the reincarnation of someone from the past in the wizarding world.
One possible scenario in this fanfiction could be that Fem Harry Potter is initially shocked by the unique and alien environment of Pandora. She might struggle to adapt to the different flora and fauna, but her magical abilities could give her an edge. For example, her ability to use magic could help her communicate with some of the intelligent species on Pandora in ways that the regular humans in the Avatar world can't. Maybe she uses spells to understand the language of the Na'vi, which could lead to interesting interactions and alliances.
He could also meet some sort of dark wizard or villain that is even more powerful than Voldemort in this new world. This would pose a great threat to Harry and force him to use all of his skills and knowledge, both from his own world and what he's learned in the new one, to defeat the enemy.
In this fanfiction, Harry Potter would interact with the Queen in a very unique way. Since he is used to the hierarchical system in Hogwarts, he would understand the importance of showing deference to the Queen. He could offer her a magical gift, like a charm that gives good luck. And the Queen, being curious, might ask him about his world. Harry would have to be careful not to reveal too much about the wizarding world to the muggles, but still satisfy her curiosity. There could be some misunderstandings too, for example, when Harry tries to explain some magic concepts using wizarding terms that the Queen doesn't understand.