Well, if Naruto got Thor's hammer in fanfiction, it would be a really interesting crossover. Naruto is known for his strong will and determination, which are important qualities to be worthy of the hammer. He might use the hammer to protect the ninja world from greater threats that his normal jutsu couldn't handle. For example, if there was a super - powerful enemy that was immune to ninjutsu, the hammer's magic could be the solution.
Yes. The breaking of Thor's hammer in the comics is part of complex and dramatic storylines. It can happen for various reasons related to the plot and character arcs.
He might gain new powers or abilities. Since the hammer is a powerful magical weapon, lifting it could unlock some latent potential within Peter. Maybe he can now control lightning like Thor, or he has enhanced strength and durability.
Fanfiction often takes creative liberties. It could be that there is a cross - over event that changes the nature of Thor's hammer's worthiness test. Maybe a powerful magical entity in the Harry Potter universe meddles with the hammer's magic. Harry Potter has shown great moral fiber throughout his adventures. His ability to love deeply, his sense of justice, and his unwavering determination against evil could be seen as the 'worthiness' factor by the hammer's magic, allowing him to lift it.
Vision cannot lift Thor's hammer in the comics. The hammer's magic is very selective, and Vision doesn't possess the qualities necessary to overcome its enchantment and lift it.