Well, first off, there's Sasuke. Their rivalry and friendship is a huge part of the original Naruto story, and as a girl, Naruto's interactions with Sasuke could range from him being over - protective to being a bit more awkward. Then there's Jiraiya. He was Naruto's teacher in many ways, and now he might have to teach a female Naruto, which could be really different. And of course, Hinata. She might be one of the first to notice the change in Naruto and could become a really good friend or even more, depending on how the story goes.
Sasuke would definitely be one of the main characters to interact with Naruto. Their relationship has always been complex, and with Naruto as a girl, it could become even more so. Sakura would also interact a lot. She might be both jealous and intrigued by Naruto's new form. Kakashi too, as Naruto's mentor, would have to adjust to this change and guide 'her' in a different way perhaps.
Obviously, Sasuke would still be a major character she interacts with. Their relationship could be even more complex now that Naruto is a girl. Sakura might also have a different dynamic with Naruto. Instead of seeing her as a rival for Sasuke's attention, they could become closer friends and train together more often.
Astrid is likely to be one of the main characters to interact with Hiccup. She might be initially very confused or even a bit jealous depending on how she perceives Hiccup's new form. Stoick, Hiccup's father, would also have significant interactions. He would probably be shocked at first but then try to support his child in this strange situation. And of course, Toothless. Their bond is so strong that Toothless would surely be involved, perhaps trying to understand what has happened to his rider.
Obviously, Koyuki herself would be a main character to interact with Naruto. She might show him around her place, introduce him to her people. Also, any of her loyal guards or advisors could interact with Naruto. They could be initially suspicious of him but then grow to trust him as they see his good intentions.
Sasuke would be a likely character to interact. Given their complex relationship throughout the Naruto series, Sasuke might be suspicious or intrigued by Naruto's control over Zetsu. Their interactions could range from confrontations to reluctant teamwork.
Well, Hinata would be one of the main characters with a different interaction. She might be more open and confident around Naruto as a girl. Tsunade could also play an important role. She might take Naruto under her wing more as a girl, teaching her things about being a female ninja. And Rock Lee might be even more eager to compete with Naruto as a girl, seeing it as a new and exciting challenge.
Sasuke would likely be one of the main characters to interact with Naruto. Given their complex relationship, Sasuke might be either supportive or skeptical of Naruto's newfound power. Sakura could also be involved, perhaps trying to heal Naruto if the dark power has negative effects on him. Kakashi would surely step in as well, using his wisdom to guide Naruto and make sure he doesn't lose himself in the darkness.
Obviously Naruto himself is the central character as the story is about him getting disowned. His friends like Sasuke and Sakura might also be involved. Sasuke could be conflicted between his loyalty to the village and his friendship with Naruto. Sakura might initially be confused about whether to side with the village or Naruto. And then there are the village elders like Danzo who could be the ones behind Naruto's disownment in the fanfic.
Sakura could be a main character. She might be the one who takes on a motherly role towards baby Naruto. She'd be very protective and try to teach him basic things. Kakashi could also be important. He'd use his wisdom to figure out how to deal with this situation and also keep an eye on Naruto's safety.
Well, in the 'naruto lifts thor's hammer fanfic', apart from Thor, other Asgardians like Heimdall could interact with Naruto. Heimdall, with his all - seeing ability, might have seen Naruto's worthiness from afar. The Hulk could also be involved. Imagine the chaos if the Hulk got jealous of Naruto having the hammer. And from Naruto's side, Kakashi could be there to guide Naruto on how to handle this new power that comes from a different world.
Sasuke would be a likely character. Their rivalry could take on a new dimension as Naruto's super intelligence might make Sasuke more intrigued or even a bit jealous. They could have more complex conversations about strategy and the future of the ninja world.