Naruto might be initially very disappointed. He has always looked up to Kakashi as a strong and cool ninja, and being refused by him would be a big blow. He could become a bit sulky and withdrawn, feeling like he's not good enough.
He may be surprised. Fanfictions can have some really out - there ideas that he might not have considered before. For instance, a fanfiction might have Naruto suddenly having a new, super - powerful jutsu that was never seen in the original series.
Kakashi would probably be very calm at first. He's an experienced ninja who has seen a lot. He'd gently pat Naruto on the back, offering silent comfort. Then he might start to speak softly, asking Naruto what's wrong in a gentle voice.
The Naruto fandom would likely be very divided. Some fans might be intrigued by this unique and unexpected plot twist, seeing it as an interesting exploration of an alternate Naruto universe. However, many fans would probably be quite shocked and even appalled, as it goes against the traditional understanding of the characters and the series.
Well, for starters, Kakashi has to deal with Naruto's hyperactive and sometimes reckless behavior. Naruto often acts without thinking, which could put him in danger. Sasuke, with his complex emotions and the burden of his clan's massacre, is also a handful. Kakashi needs to make Sasuke understand that revenge is not the only way forward. Additionally, Kakashi has to ensure that both Naruto and Sasuke get along well with each other. There could be rivalry between them, and Kakashi has to manage that in a way that doesn't harm their relationship or their growth as ninjas.
The other villages might react with a mix of shock and suspicion. They knew Naruto was a powerful force for good in the ninja world. His death could be seen as a sign that something was amiss in Konoha. Some villages might even fear that Konoha was becoming unstable and could pose a threat. Characters like Gaara, who had a special bond with Naruto, would be deeply saddened and might try to find out the real reason behind Naruto's death.
One challenge could be Naruto's stubbornness. Naruto has his own ideas and ways of doing things, and getting him to listen and follow Kakashi's guidance might be tough. Another is dealing with Naruto's past traumas. Kakashi would need to help Naruto overcome his feelings of loneliness and being an outcast. Also, Kakashi has his own responsibilities and missions, so finding time to be a proper adoptive father could be a struggle.
Another reason could be related to Kakashi's past actions. If there are some secrets or things Kakashi did in the past that come to light and Naruto doesn't like them, he could snap at Kakashi. Naruto has a strong sense of justice and loyalty, so if he feels betrayed or misled by Kakashi, his reaction could be to snap.
It could become strained. Naruto snapping at Kakashi would create an initial rift between them. Kakashi might be taken aback by Naruto's outburst and Naruto, after snapping, might feel a bit guilty but also stubborn about his feelings, which would make the relationship tense for a while.