Naruto would probably be very friendly and kind. He has a big heart, so he'd likely greet her with a big smile and start chatting right away, asking her name and where she's from.
Kakashi would be very observant. He would look for how the fanfiction writers understand the world of Naruto, the values and the moral lessons. He might even use some of the creative ideas from the fanfiction in his own teachings if he thought they were valuable and in line with the spirit of the original story.
She may start by trying to figure out who the kidnapper is and what his motives are. If she has any special abilities or skills, she would be thinking about how to use them to her advantage. For example, if she has telepathic powers, she could try to send a distress signal to her friends or family. Also, she might try to gain the kidnapper's trust in order to find a moment to escape.
Sakura might be really surprised at first. She could offer to help Naruto with his girl disguise, teaching him things like how to do his hair or choose the right clothes. She might also find it a bit funny but would be supportive in the end, seeing it as part of a mission. Sasuke, on the other hand, might be a bit more aloof. He would probably just raise an eyebrow at Naruto's new look but wouldn't make a big fuss about it as long as it was for a good reason.
Ino might be initially shocked. But then she'd probably be quite excited. She could start planning all sorts of things to do with Naruto, like shopping for new clothes or teaching her about girl - only ninja techniques. Ino would likely see it as an opportunity to have a new kind of friend.
Neji might get angry. He's a proud character, and being called a girl in a somewhat derogatory way (if that's how he takes it) could make him lash out at Naruto. He could give Naruto a cold stare and tell him to watch his words.
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.
Sasuke would likely act like he doesn't care much. But secretly, he might be a bit intrigued as to why Naruto is into such things. He might think it's a waste of time or he could see it as another way Naruto is different from him.
Sasuke might be initially shocked. But being Sasuke, he would probably keep his thoughts to himself at first and just observe Naruto's new behavior. Later, he might offer some dry comments or advice if he sees Naruto struggling with the changes. Sakura, on the other hand, would be very curious. She might try to help Naruto adjust, like teaching him how to do a girl's hair or choose appropriate clothes, while also being a bit envious if Naruto starts to get more attention from the boys in the village.
The ninja in the village, like Kakashi, would need to figure out how to handle this situation. They would have to ensure Naruto's safety while also trying to find a way to reverse the transformation. They might also have to deal with any potential threats that come as a result of Naruto's new form. For example, if other villages heard about it, they could try to take advantage of the situation.