The Hogwarts students in general would be quite intrigued by the 'Rent a Hero' concept. The younger students might look up to the 'heroes' as some kind of superstars. They would be eager to learn from them and ask for their autographs. The older students, like the members of Dumbledore's Army, would be more practical. They would consider how the 'heroes' could be used in their fight against any new form of dark magic. Some students might also be worried that the 'Rent a Hero' service could be infiltrated by dark wizards pretending to be heroes, so they would be on high alert.
Harry would be very cautious at first. He has been through so much and wouldn't trust just anyone. But if it was to save his friends or the wizarding world, he might consider it. He would probably grill the 'hero' on their motives and abilities. Hermione would approach it analytically. She would want to know all the rules and regulations of the 'Rent a Hero' service and study how it works before getting involved. Ron, on the other hand, might be more easily swayed by the idea of having a 'hero' around, especially if it meant getting out of a tough situation or getting some glory.
One possible plot could be that a wizard has the ability to 'rent a hero' from a magical service. Harry Potter himself could be rented out to help a young, struggling wizard face a new dark threat in the wizarding world. He could use his skills and experiences to train this wizard and together they could uncover a plot by a group of Death Eaters who are trying to revive Voldemort in a new way.
The characters would interact in very strange ways. The Hogwarts students would be shocked by the Jackass crew's behavior. The Gryffindors might be initially intrigued, while the Slytherins would be disdainful. Harry and his friends would probably try to keep the Jackass guys out of trouble, but it would be difficult as they are always looking for the next wild thing to do.
Harry might be in awe of Elsa's powers at first. He would likely approach her with caution and respect, as he does with most powerful beings. Elsa, on the other hand, would be curious about Harry's world of wands and spells. They could start by sharing their stories. Harry would talk about Voldemort and his battles, and Elsa would share her experiences with her frozen kingdom and her isolation.
The Stargate characters are used to dealing with advanced technology and alien cultures. When they meet the Harry Potter characters, they might be initially confused by magic. For example, Jack O'Neill might be both amused and intrigued by the spells the wizards cast. Meanwhile, Harry Potter and his friends would be curious about the Stargate technology and the different worlds it can access.
The magic could enhance the technology. For example, a spell could be used to make Baymax's healing capabilities even stronger. Or the magic could be used to power up the Big Hero 6's gadgets in a way that normal power sources couldn't. Maybe a simple levitation spell could be applied to their flying machines to make them more efficient.
The interaction could be initially very tense. The Prime Minister might be skeptical and afraid of Harry Potter and the magic he represents. But as the story progresses, he would start to see Harry as an ally. For example, Harry might have to perform some magic in front of the Prime Minister to prove the existence of the wizarding world, and the Prime Minister would be both amazed and a bit intimidated. Later, they would communicate more freely, with Harry explaining the ways of the wizarding world and the Prime Minister sharing his concerns about how magic can impact the Muggle society.
Hikaru is very observant, which could be useful in the wizarding world. He might notice small details about the magic around Hogwarts that Harry has overlooked. In return, Harry could teach Hikaru more about the serious aspects of magic, like defense against the dark arts. Their interactions would be a mix of cultural exchange, with Hikaru sharing his Japanese school experiences and Harry introducing the wizarding world traditions, and also a combination of their different personalities clashing and then meshing together as they face various challenges at Hogwarts.
Harry Potter would probably be initially cautious around She - Hulk. He's used to magic and magical creatures, but She - Hulk is a whole new level of different. However, as he gets to know her, he would respect her strength and her sense of justice. She - Hulk, on the other hand, would be amazed by the magic in the wizarding world. She might try to learn some spells and would be very protective of Harry and his friends, just like she is in her own world.
Jacob would likely be very direct and physical in his interactions, while Harry might be more cautious and cerebral. Jacob could introduce Harry to the world of werewolves, and Harry could show Jacob the magic of the wizarding world. They might start off being a bit suspicious of each other, but as they face challenges together, they would grow to respect and rely on one another.
The Ghostbusters would probably be really confused at first when they enter Hogwarts. They might start trying to figure out how all the magic works. Harry Potter and his friends would be equally curious about the Ghostbusters' equipment. Hermione would probably be asking a million questions about how the proton packs work. And the Ghostbusters would be shocked by things like the moving staircases and portraits that talk.