He may be confused at first. Fanfics can be very different from his real experiences. He might wonder why people write such things about him and his world.
Well, Harry Potter is a rather humble character. He might initially feel a bit embarrassed to see himself as the center of so many fictional stories created by fans. If the fanfic portrays him as a hero in new adventures, he would probably be honored. However, if it misrepresents his friends or the values he holds dear, he could be a bit indignant. He would likely approach it with an open mind but also with a sense of protectiveness towards his own story and those he loves.
Perhaps the travel agent is a bit of a troublemaker. Instead of suggesting normal wizarding travel destinations, they might try to persuade Harry to visit some off - limit or even illegal magical places. They could tell him about a secret portal to a dimension where dark magic is still being practiced freely, which of course, Harry would have to resist.
Hermione would probably be both curious and worried. She'd want to research all about Harry's half - demon nature to find out what it means and how to help him. Ron, on the other hand, might be a bit more hesitant at first. He might be a bit scared but would eventually come around because of his loyalty to Harry.
There's a chance he'd be inspired. The stories of the Naruto characters' determination and growth in the fanfiction could stir something in him. He might think about his own journey as a wizard and how he can further develop his skills and character, taking cues from the Naruto characters' tenacity.
Well, Harry could react with a great deal of suspicion. Since he and Snape have had a rocky relationship, he might think Snape is up to no good. He could try to gather his friends, like Ron and Hermione, to help him figure out what Snape's real motives are. Harry might also try to use his own wits and magic skills to outsmart Snape if he feels that Snape is being unfair or dangerous in his forcing of actions. He could also be very conflicted, on one hand wanting to trust Snape as Dumbledore did, but on the other hand being very wary due to their past interactions.
If Harry is turned into a weapon, Ginny would be heartbroken. She would be by his side constantly, trying to communicate with him even though he's in weapon form. The Weasley family as a whole would be outraged. They would see it as an attack on one of their own. Snape might initially seem indifferent but secretly would also try to find a way to reverse it, perhaps out of his complex feelings towards Harry and his loyalty to Dumbledore.
He might become withdrawn. Harry has been through a lot in his life, and being heartbroken by Fleur could make him retreat into himself. He may avoid his friends and isolate in his dormitory at Hogwarts.
Hermione would be extremely curious. She would immediately start researching it, trying to figure out its mechanics and where it came from. She might even try to find a way to improve it or adapt it to the wizarding world's technology.