Sakura would be heartbroken. She'd likely spend hours upon hours by Naruto's side, trying to jog his memory with stories of their adventures together. She might even get a bit overbearing in her attempts. Sasuke, who has his own complex relationship with Naruto, would be conflicted. He'd see Naruto's forgetfulness as a sign of weakness at first but then realize the importance of their bond. Kakashi, being the experienced leader, would start by observing Naruto carefully to see exactly how much he has forgotten and then start a systematic process of helping him remember.
Sakura would be in shock and then quickly turn to action. She'd search through all her medical texts and consult with other medical ninjas to find a cure for Naruto's memory loss. She'd also be very emotional, constantly reminiscing about their time together to Naruto in the hopes of triggering his memory. Sasuke would initially be aloof, but as he realizes the implications of Naruto forgetting Team 7, he'd become more involved. He might even use his Sharingan in some way to try and probe Naruto's mind. Kakashi would take charge, guiding the other two members of Team 7 in their efforts to help Naruto. He'd also be the one to keep their spirits up during this difficult time.
They would be shocked at first. Minato would be filled with pride and joy seeing his son all grown up. Kakashi would respect Naruto's strength. Obito might be a bit envious of Naruto's popularity but also admire his spirit. Rin would be very friendly towards Naruto.
When Team Minato meets Hokage Naruto in a fanfiction, their reactions would depend on their individual personalities. Minato would be overjoyed and would immediately start asking Naruto about his achievements and how he has led the village. Kakashi would be his usual calm self but would show his admiration through his words and actions. Obito, who has had a difficult journey, might initially be hesitant but then would be inspired by Naruto. Rin would be the most excited, perhaps jumping up and down and saying how wonderful it is that Naruto is the Hokage. This encounter could also lead to a deeper understanding between them all and a strengthening of the bonds between generations.
Sasuke would likely be devastated. Despite their past differences, Naruto was his rival and in a way, his closest friend. He might go into a deep state of regret and isolation. Sakura would be heart - broken. She loved Naruto, and his death would be a huge blow to her. She might become more withdrawn and focus all her energy on her medical ninjutsu. Kakashi would be filled with a sense of failure. He was Naruto's teacher, and he would feel responsible for not being able to protect him.
Sasuke might initially be indifferent on the surface, but deep down he would feel a sense of loss. He has always had a rivalry with Naruto, and Naruto's departure would mean an end to that dynamic. Sakura would be devastated. She has grown to care about Naruto as a friend and teammate, and his leaving would leave a big hole in the team.
They would be empathetic. Minato, as Naruto's father, would especially feel a deep sense of pain seeing his son struggle. He would want to reach out and comfort Naruto during his lonely times when the village shunned him because of the Nine - Tails.
After the initial shock, Naruto could become determined to prove his innocence if that was the case. He's a fighter, and he wouldn't just let this false accusation or betrayal stand. He might set out on a journey to find the truth and clear his name, all while struggling with the pain of his friends' actions.
One possible plot twist could be that Naruto's memory loss leads to him accidentally endangering his former teammates. For example, he might unknowingly reveal secrets to the wrong people. Another could be that his forgotten bond with Team 7 causes him to form new alliances that are initially at odds with his old team. Maybe he teams up with former enemies who manipulate his lack of memory. Also, it could lead to a situation where Team 7 has to reteach Naruto about their shared past and values, which would be a really emotional and character - developing journey for all of them.
At first, Naruto would be extremely hurt. He has always considered Team 7 as his family, so their betrayal would be a huge blow. He might go into a state of shock and disbelief.
Well, Sasuke might initially be a bit shocked but then he'd try to hide his concern. Sakura would be very empathetic and might immediately want to do something to help Naruto. Kakashi, being the experienced one, would take a more calm and strategic approach to deal with Naruto's situation and protect him from further abuse.
Sakura would probably be a bit jealous at first. She's always been competitive with Naruto in terms of power growth. But then she'd realize the potential of lava release and be supportive, offering her medical skills to help Naruto train without getting seriously injured. Sasuke would be intrigued. He might see it as a new challenge and start thinking of ways to counter Naruto's new ability in case they ever spar or fight in the future.