Well, in such a fanfiction, Itachi might kidnap Hinata for various reasons. Maybe he's being controlled by some dark force and needs Hinata for some ritual. Or perhaps he's been misinformed that Hinata has some special power that can help him in his secret mission against the Hidden Leaf Village.
The Hyuga clan as a whole might also take action. Neji, for example, being Hinata's cousin, would feel responsible for her safety. The Hyuga have their own techniques and strength. They could mobilize their forces to track down Itachi and rescue Hinata, especially since she is an important member of their clan.
Well, one possibility could be that Itachi has some hidden motive related to the Uchiha clan's secrets. He might think Kakashi knows something crucial. So, he kidnaps him to interrogate him in a secret location.
Well, one possibility is that Itachi has some hidden motives. Maybe he believes Sakura has knowledge about something important in the ninja world, like a secret jutsu or information about an enemy. So he kidnaps her to extract that information.
At first, Hinata's reaction might be one of shock and disbelief. She has probably never expected Sasuke to do such a thing. However, she is a strong - willed character deep down. So, she might start to plan her escape. She could use her knowledge of the ninja world and her own family's techniques. She might also try to find out if Sasuke has any allies or if there are other forces at work. She could try to turn the situation around and make Sasuke realize that what he is doing is wrong by appealing to his better nature or by using her own skills to outwit him.
Itachi himself could be seen as the main antagonist in this scenario as he is the one carrying out the kidnapping. He is acting against Sakura's will and causing a dangerous situation for her.
Well, in this fanfiction, perhaps Itachi is being manipulated by some dark force. He kidnaps fem Naruto because he's under the control of this force which thinks that Naruto, being female in this version, holds the key to some sort of ancient prophecy. Itachi is then in a struggle between his loyalty to the village and the commands of this dark entity.
Naruto might initially be shocked and angry. He has a strong sense of justice and being kidnapped goes against everything he stands for. He would likely try to fight back immediately, using his basic ninja skills and his determination. For example, he could try to use his Shadow Clone Jutsu to create distractions and escape.
Naruto would likely be involved. He has a strong bond with Kakashi and would surely try to rescue him. Sasuke could also be part of the story. Given his relationship with Itachi, it would add an interesting dynamic.
Another possibility is that an old enemy of the Uzumaki clan resurfaces. They use Itachi's complex relationship with the village and his own motives to manipulate him into kidnapping fem Naruto. So, this old enemy would be the main antagonist as they are the ones driving the overall conflict.