Definitely Hinata. Her gentle yet strong - willed nature could be an interesting contrast when dealing with the often - mischievous yokai from Nurarihyon. Gaara too, as his own experiences with being an outcast and having a powerful force within him could have parallels in the Nurarihyon world where some yokai are feared or misunderstood. And Rock Lee, his determination and unique fighting style could bring a new dynamic to the interactions in the fanfic.
Kakashi could also be involved. Maybe he's put in a difficult position where he can't save Naruto for some reason, like being under a powerful genjutsu or being blackmailed. This would create an interesting conflict as he's Naruto's teacher and mentor.
Well, characters like Jiraiya could be really interesting in a 'naruto crossover godlike fanfic'. He has a lot of knowledge about the ninja world and different powers, so his encounter with god - like beings would be full of potential for interesting stories. Tsunade too, as a powerful Hokage, could be involved. She could represent the Naruto world's power structure when dealing with these otherworldly god - like entities. And then there's Orochimaru, who is always seeking more power, so he would be very likely to get involved in any situation where there are god - like powers to be had.
Naruto and Sasuke are very likely. Their contrasting personalities and styles make a clothes swap between them full of potential. It would be a great way to show their differences and similarities in a new light.
Gaara could also be part of the fanfic. Since he has his own unique abilities related to sand, there could be an interesting interaction between his powers and Naruto's summoned creatures. For example, Naruto could summon a water - based creature and they could team up with Gaara to fight an enemy that is strong against both sand and water.
There could also be some new characters created specifically for the fanfic. Maybe a foreign diplomat who comes to Konoha and Naruto is the first one to welcome him and befriend him. This would open up new storylines about international relations in the Naruto world and how Naruto's friendship can have a positive impact on a larger scale.
Naruto is the obvious one. His connection to the Uzumaki clan makes him the driving force behind the rebuilding. Hinata would also be likely involved, as Naruto's wife, she would support him and might contribute to the new Uzushiogakure in areas like family support and community building.
Obviously Naruto himself is the central character. Sasuke would also likely be involved. Given their history and Sasuke's own complex relationship with Konoha, he might side with Naruto or at least be a key figure in the events. Kakashi too, as he has been Naruto's teacher and is an important figure in Konoha. He could be caught in the middle, trying to understand Naruto's motives and also trying to uphold Konoha's stability.
Obviously, Naruto is the central character. But other characters like Sasuke could also be involved. Sasuke might be torn between his loyalty to Konoha and his friendship with Naruto. He could either try to bring Naruto back or join him in his exile.
Sasuke is a very likely character. He already has a strong connection to hate in the original series due to his clan's massacre. In a fanfic about the power of hate, his journey could be further explored, like how he might be tempted by even darker forms of hate - driven power. Another one is Obito. His fall into darkness was also driven by hate, and in a fanfic, his character could be used to show the extreme lengths that the power of hate can take someone.
In a 'naruto finally snaps fanfic', Naruto is the main focus, but characters like Kakashi would be involved. Kakashi has been Naruto's teacher and mentor, so he would be affected by Naruto's change. Also, characters from other villages such as Gaara could be part of the story. Gaara has his own connection with Naruto, and Naruto's snapping would have an impact on their relationship and the balance between villages.