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 She might become more withdrawn and focus all her energy on her medical ninjutsu.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.
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.
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.
Naruto would likely be devastated. His old team was an important part of his early life in the ninja world. He might initially go into a state of shock, unable to believe that they are gone. Then, his grief could turn into anger, vowing to find out who was responsible and make them pay.
Sakura's reactions can vary. Sometimes she tries to get revenge on Naruto for his pranks. If he plays a prank that makes her look silly in front of Sasuke, like the fake love letter prank, she'll be really mad and try to think of a way to make Naruto pay. Sasuke might pretend not to care, but if the prank affects his image too much, like the hair product switch, he'll give Naruto a cold stare. Kakashi is more laid - back and just watches the whole thing unfold like it's entertainment.
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.
Naruto would probably be overjoyed at first. After all, he has always longed for his parents. But with the sister, it might be a bit more complicated. He might be a bit cautious, not sure how to interact with her at first. But eventually, he would welcome her into his life with open arms.
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.
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.
Naruto could also feel a bit sad and lonely. He's used to being an outcast in the village, but he thought Team 7 would be different. So he might start to question himself. Maybe he'd start training on his own more, trying to become stronger so that they would have to notice him. And he might also try to find other friends outside of Team 7 to fill the void.