One way could be to use the idea of 'freedom' in the Naruto context. For example, the shinobi in Naruto are often restricted by their village rules and missions. A fanfic could explore a character's journey to break free from these constraints in a way similar to the concept in 'The Sound of Freedom'.
There might be some extremely niche Naruto fanfics related to 'The Sound of Freedom', but I haven't come across any. Naruto fanfics typically revolve around ninja battles, character relationships within the Naruto world, like Naruto and Sasuke's friendship - rivalry, or the development of new jutsus. 'The Sound of Freedom' is about a different topic altogether. So, while the world of fanfiction is vast and unpredictable, it's not very likely to find a lot of Naruto fanfics related to it.
It's based on a true story. The movie highlights the real - world issue of child trafficking. However, like any movie adaptation, some elements might be dramatized for the sake of the narrative.
I'm not sure. It depends on how the story was developed and presented. Some elements might be based on real events, but it could also have fictional parts.
Yes, it is. Sound of Freedom takes its roots from actual occurrences and attempts to present a realistic portrayal of the fight against injustice. Though it may have added some fictional elements for storytelling purposes, the core of the story is true.