Snape could also be the one to teach Harry a lesson. Given their complex relationship in the original books, in fanfiction, Snape might see an opportunity to put Harry in his place. For instance, if Harry fails in a potions class because of his carelessness, Snape could use this as a chance to teach him about discipline and attention to detail.
Well, Hagrid would be a great addition. He could bring in some friendly magical creatures for the preschoolers to see, like baby owls or small unicorns. The kids would be thrilled to meet them.
Maybe Harry would teach Tom about the consequences of dark magic. Since Harry has faced Voldemort multiple times and seen the destruction caused by dark spells. He could use these real - life (well, in the wizarding world) examples to make Tom understand that there are other paths in magic that are more positive and life - affirming.
His creativity would likely expand. Since he's teaching himself fanfiction, he would start to view his own world from different perspectives. This could make him more empathetic towards others in the wizarding world as he tries to understand different characters' motives and feelings through writing.
Perhaps Harry is teaching Potions in the fanfiction. Since he had a bit of a rocky start with Potions in his student days, he could be a very understanding teacher. He might encourage students to experiment more, which is different from Snape's strict methods. He could also share stories about how important Potions were in his adventures, like when they made Polyjuice Potion. This would make the class more interesting and inspire students to take Potions more seriously.
If Harry Potter teaches at McKinley in fanfiction, it would be a total chaos in a good way. The students there are used to a normal school life. Harry would bring in Quidditch and the students would be thrilled. He could also teach them about the different magical creatures, which would be a whole new world for them. And of course, his Defense Against the Dark Arts classes would be legendary.
Obviously, Harry Potter is the main character as he is the one doing the teaching. His students would also be important characters. This could include well - known characters like Neville Longbottom, who might struggle at first but then thrive under Harry's teaching. Ginny Weasley could also be a prominent student in the class, showing great skill and courage.
Maybe Harry Potter could teach the preschoolers magic tricks in a simple and safe way, like making feathers float. He could also tell them stories about Hogwarts and his adventures, inspiring their imagination.
In the fanfiction, if Harry Potter teaches at Ouran, he would probably struggle with the very different culture. Ouran is all about high society and luxury, while Harry comes from a more humble background. However, he could use this difference to his advantage. He could introduce the values of loyalty and friendship that he learned at Hogwarts. He might form a club where students can learn about different forms of courage, both the Gryffindor - like boldness and the quieter, more patient courage that comes from facing everyday challenges. This would be a great way to bridge the gap between the two very different worlds he's now a part of.
Hermione would surely be a main character. She could be a fellow teacher, perhaps teaching Transfiguration or History of Magic. She would be the one Harry goes to for advice on teaching methods or when he has a difficult student. Another character could be Ron. He might visit Harry at Hogwarts and end up getting involved in some of the school's mysteries or helping Harry with a particularly difficult Quidditch - loving student.