Well, Naruto is the main one. But also, Kakashi could be involved. He might be a bit amused at first but then help Naruto figure out how to use his new body to his advantage in combat. And then there's Hinata. She could have an interesting reaction, perhaps being more shy around Naruto as a girl, or she could be more empathetic as she also has her own insecurities.
One interesting plotline could be Naruto trying to adapt to the social and physical differences of being a girl while still maintaining his ninja skills. For example, he might have to learn new ways to fight as his body is now different. Another could be how his friends react to this sudden change, like Sasuke being initially confused but then coming to accept Naruto's new form.
Another plotline could be centered around Naruto's relationships. As a girl, she might attract different kinds of attention from male characters. This could create some comical or even tense situations, especially if Naruto is still trying to maintain his focus on becoming Hokage while also dealing with these new romantic or platonic interests.
Iruka sensei could also be very helpful. He has always been like a father figure to Naruto. He would support Naruto through this strange transformation, offering advice on how to handle the reactions of others in the village and how to adapt to this new situation without losing sight of his ninja goals.
Well, the plot could involve Naruto waking up one day in a female body. He might struggle to adapt to the new physical form at first. Maybe he has to deal with different reactions from his friends, like Sasuke being really confused. And he could face new challenges in his ninja training, as his body now has different capabilities and limitations compared to when he was male.
It could be Orochimaru. Orochimaru is always interested in strange experiments and new forms of power. He might see Naruto in his female form as an interesting specimen to study or use for his own evil purposes.
In this fanfiction scenario, Naruto and Hinata might face a lot of challenges while stuck in the box. Maybe they'd first try to find a way to communicate with the outside world. Naruto, with his never - give - up attitude, would likely start looking for any weak points in the box to break through. And Hinata, being calm and observant, could be searching for any hidden mechanisms or clues within the box.
In addition to the main ones, characters like Shampoo and Ukyo might play important roles. Shampoo, who has her own feelings for Ranma, may have a different approach to a female - Ranma. Ukyo too, might have a new dynamic with Ranma in this situation. And of course, there could be other minor characters from the original series that get involved in the fanfiction, depending on the author's creativity.
One possible plotline could be Ranma trying to participate in all - female sports teams or activities while stuck as a girl. Another could be the comical misunderstandings that arise when her male friends don't recognize her at first.
One possibility could be that they are trapped in an alternate dimension created within the fanfiction. Maybe they have to face new and strange enemies that don't exist in the original Naruto world. For example, they might encounter powerful magical creatures that are a product of the fanfiction writer's wild imagination.