Well, one major fact is that the operation to get Bin Laden was real. But in terms of fiction, some of the details about how the intelligence was gathered in the movie might be dramatized. For example, the movie might have compressed the time frame of certain events for the sake of a more engaging narrative.
I think young Sasuke would have a very intense reaction. He was so consumed by his hatred for Itachi at that young age. A Sasuke vs Itachi fanfiction would be like a trigger for him. He would be eager to see how the fictional fight is portrayed. If Sasuke in the fanfiction is shown as strong, it might fuel his own ego and make him strive even harder to become powerful. However, if the fanfiction shows Itachi as superior, it could enrage him. He might feel that it undermines his own goal of defeating Itachi and he might even want to find the writer to correct their 'wrong' view.
Perhaps the Fairy Tail members watching will have different reactions. Some might be worried for Natsu, especially those who are close to him like Lucy or Happy. Others, like Erza, might be more focused on analyzing Natsu's moves and Zero's counter - attacks. And there could be some comic relief from the likes of Gray, making snarky comments while still being engaged in the fight between Natsu and Zero.
Some characters might be flattered. For instance, Rem would probably be happy to see positive portrayals of her loyalty to Subaru. Others, like Roswaal, might be intrigued by the different theories and storylines in the fanfic that revolve around him.
His friends would likely be very concerned. They might immediately rush to his side to check on his injuries. For example, they could call for medical help or try to stop any bleeding if it's a more serious wound. They would also offer words of encouragement and support, telling him not to worry and that he'll get better soon.
Naruto himself would probably be excited. He'd see all the magic and different creatures as new challenges and opportunities. He might try to befriend all the familiars and show them his ninja skills.
He'd probably be very intrigued. Percy has a penchant for adventure and new things, and this fanfiction would be something completely different from what he's used to.
The unique interactions. When Fairy Tail characters watch Natsu vs Zero, their reactions add depth. For example, if Lucy gasps or looks worried, it shows her care for Natsu.
There were some ancient novels similar to Betraying Buddha and Desire Buddha that could be recommended. Among them," After the Holy Monk was poisoned " told the story of the female protagonist solving the male protagonist's gu poison, fighting monsters along the way to level up and collect treasures. The Skyhill Banquet was a large-scale ancient novel that told the story of a female official and a swordsman in the Jianghu. These novels might satisfy your reading needs for similar topics.