Neither of them conforms to typical mainstream simplicity. Funny Valentine's actions and motives are deeply rooted in the complex lore of JoJo's. Pulp Fiction's plot structure and character development are far from the ordinary Hollywood formula. They both break away from the norm, whether it's in the context of a manga/anime or a movie.
He probably wouldn't fit in well at first glance. Pulp Fiction's world is more grounded in a somewhat realistic, albeit highly stylized, criminal underworld. Funny Valentine, with his supernatural abilities from JoJo's Bizarre Adventure, would be an outlier. But if you think about it, he could potentially be a new kind of power - hungry antagonist in the seedy criminal world, using his stand powers to manipulate situations for his own gain.
In a fanfic where Naruto is trained by Vincent Valentine, the story could take some exciting turns. Vincent's experience and skills could help Naruto expand his understanding of combat beyond what he learned in the ninja world. For example, Vincent's knowledge of the Lifestream could give Naruto new insights into the energy in his own world, like chakra. Naruto might also adapt Vincent's stealth and infiltration techniques, which would be a great addition to his ninja skills. This could lead to new and thrilling adventures as Naruto uses these combined skills to face stronger enemies and protect his village in ways he hadn't thought of before.
In fanfiction, the Rinnegan is often depicted as more powerful than the Sharingan in many ways. The Rinnegan has abilities like the Six Paths techniques which can be extremely overpowered. For example, it can allow the user to control gravity, summon large creatures, and even revive the dead. While the Sharingan has its own set of cool abilities like predicting movements and casting genjutsu, it seems limited in comparison when it comes to the grand scale of power shown by the Rinnegan in most fanfictions.
In a fanfiction, the aliens could capture Naruto and try to study his unique abilities. The monsters then decide to rescue him because they realize his powers could be the key to defeating the aliens once and for all. The story could involve a lot of action as the monsters infiltrate the alien base to save Naruto.
The most memorable part in my picnic Valentine's story was when the ducks actually managed to snatch a piece of bread right out of my hand. We were both so shocked and then burst into laughter. It was such an unexpected and funny moment.
One possibility is that Naruto would spend the day training. He's always been dedicated to getting stronger, and Valentine's Day might be no different. He could be out in the forest, practicing his new jutsu, lost in his thoughts about how to protect his friends and the village.
One common theme is self - improvement. Both Sakura and Naruto are constantly striving to get better in these fanfics. For example, Sakura might be trying to improve her combat skills to be on par with Naruto. Another theme is friendship. Despite their rivalry, their underlying friendship is often explored. It shows that they can compete and still care for each other.
Naruto may write letters to his friends who are away. He could pour his heart out in these letters, talking about how much he misses them and how he's doing. Writing can be a very therapeutic way to deal with loneliness. He might even include some little drawings like he used to do when he was a kid.