One possibility is that Harry is exploring the Muggle world more and decides to buy Grunnings out of curiosity. Maybe he wants to understand his uncle Vernon's world better. He could use magic in secret to improve the business operations and make it a more efficient place, all while keeping the Muggles there oblivious to the magic involved.
Harry could be interested in the Muggle technology used in Grunnings. As a wizard, he has seen magic all his life, but the Muggle way of doing things fascinates him. Buying Grunnings gives him a chance to study and perhaps even combine Muggle technology with magic in some innovative ways.
I'm not entirely sure what 'grunnings fanfiction' specifically means in this context. It could be a very niche or made - up concept within the Harry Potter fan community. Maybe it implies that Harry Potter has some sort of connection or ownership within a particular type of fan - created story related to Grunnings, which was his uncle's company.
In this fanfiction, Harry Potter might be facing a new situation in the Muggle world. Buying a car could be a sign of his further integration into Muggle society. Maybe he uses his wizard money to buy a really cool and unique car, like a classic convertible.
Ron might be there too. He could use his skills in handling magical creatures to populate the island with friendly ones. And he could also help with fishing in the surrounding waters using magic, providing food for those on the island.
I think it could mean that within the realm of fan - made stories, Harry Potter has some sort of control or special relationship with fanfiction centered around Grunnings. Maybe it's a story where he stumbles upon these fanfictions and decides to take charge of them for some reason.
Yes, there might be. The Harry Potter fandom is vast, and fanfiction writers come up with all sorts of creative and unique ideas. You can try searching on popular fanfiction websites like Archive of Our Own or Fanfiction.net. There could be a story where Harry Potter is involved in buying a marriage contract in some alternate universe or as part of a very different plotline created by the fanfiction author.
In fanfiction, Harry owning Grunnings could potentially be a very interesting plot twist. It might symbolize his connection to his muggle roots in a more powerful way. Maybe it gives him a source of income in the muggle world and also a way to keep an eye on the Dursleys without them knowing.
It depends on the author's imagination. Maybe there's a new opportunity elsewhere or some crisis in the current location that prompts the move in the fanfic.
One challenge would be the goblins. They are very protective of Gringotts and would not easily give up control. They have their own laws and traditions regarding ownership. Harry would have to deal with their resistance and find a way to convince them or negotiate with them.