Naruto might react with a sense of responsibility. If he saw a future where Konoha was in danger, he would feel it was his duty to do something about it. He could start by gathering information from the future vision, like the weaknesses of the enemy. Then, he would share this knowledge with his comrades and come up with a plan to protect the village.
His friends like Kakashi would be cautious yet supportive. Kakashi would likely give Naruto advice on how to handle the relationship and the responsibilities that come with it. In Kirigakure, Mei's comrades might initially be distrustful of Naruto, but as they see his good intentions and how he treats Mei, they would gradually accept him. And Naruto's friends from other villages he has befriended over the years would see it as a positive step towards a more unified ninja world.
Kakashi would be more of a supportive figure. He has seen Naruto and Sakura grow up, and he would likely be happy for them. He might offer some advice to Naruto on how to handle this new relationship, especially considering the challenges they might face as ninjas. For Sakura, he could give her words of encouragement to be true to her feelings.
Sasuke might initially be a bit aloof but secretly be happy for them. He's always had a complex relationship with Naruto and Sakura, and deep down, he would see that they are good for each other.
Naruto would probably have a range of reactions. He could be excited to see new adventures that people have written for him. But if the fanfiction was inaccurate about his character, like making him cowardly when he's known for his bravery, he would likely be a bit miffed. He might also be curious about the new relationships with other characters that the fanfiction presents.
Naruto would be excited and ready to face whatever comes. He's always been positive and believing in his ability to change things. So, he'd see it as a challenge to make the future better.
At first, Naruto would be in disbelief. He has always trusted his friends wholeheartedly, so this would be a huge blow. He might then feel a deep sense of anger and sadness. However, Naruto being Naruto, he would likely also start to look for ways to prove his innocence or the misunderstanding. He might go on a journey of self - discovery to figure out what went wrong and how he can win back his friends' trust, all while dealing with the pain of the betrayal.
His friends' reactions would vary. Hinata would be really happy for Naruto. She would be gentle with the little girl and offer to make her clothes or cook for her. Kiba might be a bit skeptical at first, thinking Naruto might not be fully prepared for raising a child. But when he sees how much Naruto cares, he would be more accepting. Choji would probably be excited and share his snacks with the little girl right away, showing his warm - heartedness towards Naruto's new family member.
Shikamaru would likely be the voice of reason. He would tell Naruto to think things through clearly and help him come up with strategies for dealing with the new situation. Choji might bring over some food to help Naruto out, as he knows how difficult it can be to take care of a child. Ino would be more interested in the child's appearance and would offer to help Naruto with things like shopping for the child's clothes.
Sakura might tease Naruto about it a little. She'd probably think it's a bit strange that he's interested in something so different from their own world. But she'd also be curious to know what it's all about.