Well, Madame Maxime, the headmistress of Beauxbatons, would surely be an important character. She would be in charge of Naruto's stay at the school and would have to deal with any chaos he causes. Also, there could be a young Beauxbatons student who is a bit of an outcast and bonds with Naruto over their shared feelings of being different. This student could then be part of Naruto's adventures within the school.
Besides Naruto, a group of Beauxbatons students who are part of a secret club within the school could be main characters. They might initially be suspicious of Naruto but then realize his potential and recruit him into their club. And Hagrid from the Harry Potter universe could make an appearance as he has connections to different magical schools. He could be the one to help Naruto understand the differences between the ninja world and the wizarding world.
One of the main characters could be Fleur Delacour. Since she's from Beauxbatons, she might be the one to first interact with Naruto. She could be curious about his strange abilities and help him adjust to the school. Another could be a male student at Beauxbatons who is initially jealous of Naruto getting all the attention but later becomes his friend after seeing his true character.
In a 'naruto attends beauxbatons' fanfiction, Naruto could arrive at Beauxbatons by accident, perhaps through a strange magical - ninja portal mishap. Once there, he'd stand out with his orange jumpsuit and headband. He might get involved in a mystery within the school, like a series of disappearances. His ninja senses and skills would come in handy in investigating. He could also have a romantic sub - plot with one of the Beauxbatons girls, who is intrigued by his brash and brave nature.
Bulbasaur - girl might be a great choice too. Her connection with nature and plant - based attacks could add an interesting dynamic. She could help Naruto understand the Pokemon world better, especially when it comes to things like finding herbs or dealing with forest - related challenges. There could also be a fiery - tempered Charmander - girl who provides a contrast to Naruto's more easy - going nature and has her own set of powerful fire - type attacks.
Madame Maxime, the headmistress of Beauxbatons, would surely play an important role. She might be initially skeptical of Hermione but later come to respect her. Also, there could be a young male wizard at Beauxbatons who is intrigued by Hermione's intelligence and Hogwarts - style magic. He could try to learn from her and in the process, they become friends and face challenges together in the school.
Madame Maxime, the headmistress of Beauxbatons, could play an important role. She could be a mentor to Harry, guiding him in his new magical studies at Beauxbatons. She might also be involved in some sort of conflict or mystery that Harry has to help her solve, which could involve the relationship between Beauxbatons and other wizarding schools or some ancient magic within the school.
Obviously, the Jedi who adopt Naruto would be main characters. For example, a Jedi Master like Obi - Wan Kenobi could be the one to discover Naruto and take him under his wing. Another could be Yoda, who would be very interested in Naruto's unique abilities and would play a role in his training. There could also be other young Jedi trainees who become Naruto's friends or rivals during his time at the Jedi temple.
Sasuke could be one of the main characters. He might initially be skeptical about Naruto's new identity but then come to accept it and fight alongside him. Sakura could also be there, perhaps using her medical skills to help Naruto when he gets injured during his adventures related to his Pegasus heritage.
There could be a leader of the horde. This character might be initially skeptical of Naruto but later comes to respect him. Another character could be a young member of the horde who looks up to Naruto as a role model and wants to learn from him.
Maybe there are new characters created specifically for this fanfiction. They could be local inhabitants of the wet area, such as a water nymph - like character who has knowledge about the secrets of the place and either helps or hinders Naruto's journey.
Lelouch could be a main character. Since he is a key figure in the Code Geass world which has Britannia. He and Naruto might start as rivals due to their different approaches to justice but later become allies. Suzaku could also be involved. He might be initially suspicious of Naruto but come to respect him as Naruto shows his good intentions in the Britannian world.
Hinata could be one of the main characters. She might support Naruto in his efforts to rebuild the Whirlpool Village, both morally and with her Byakugan skills which could be useful for scouting and security.