He might interact with Luna Lovegood. She's always open to new and interesting conversations, and she could approach Harry when she sees him alone.
Well, it might be that Harry decides to go stag because he doesn't want to be tied down by the traditional ball - going - with - a - date idea. At the ball, he might discover a new side of the event, like exploring parts of the venue that are usually overlooked. He could also end up helping out some other students who are in a bind, which would show his kind nature.
The wizard Gandalf would be an obvious character for Harry to interact with. They are both wizards, though from different worlds. They could share their knowledge of magic, and Gandalf could guide Harry in the ways of Middle Earth while Harry could introduce some new magical concepts to Gandalf.
In this fanfiction, Harry might meet students from various backgrounds. There could be students from far - off magical lands who have their own unique cultures and magic. He could also run into some Beubaxtons alumni who come back to visit and they might share some interesting stories or give him some advice on how to make the most of his time at Beubaxtons.
He could meet his future self. This would be a very interesting encounter as he could learn from his future self about what he has accomplished and what mistakes he should avoid. He might also meet the future generations of his family, like his grandchildren or great - grandchildren.
Perhaps Harry will run into an old wizard who has been in the hospital for a long time. This wizard has a lot of stories about the old days of the wizarding world and gives Harry some valuable advice.
Well, in fanfiction, when Harry goes alone to the ball, he could end up being the center of attention in an unexpected way. Since he's alone, people might be curious about him. He might also use this time alone to observe the other characters more closely, learning secrets or motives that he wouldn't have noticed if he was with friends. And who knows, he could start a new trend of going solo to the ball, making others think it's a cool and independent thing to do.
Maybe he'll run into a group of young witches and wizards who are on an adventure of their own. They might team up with Harry and together they explore the new country. There could also be a wise old witch who lives in a secluded magical cottage and gives Harry some valuable advice about the country's magic and its history.
He could meet other Hogwarts students. They might be shopping for the same event or just casually browsing. It would be fun to see him interact with Hermione and Ron in a non - school - related setting like a clothes shop.
In this fanfiction, Harry could meet ancient Aztec spirits that have been bound to the temple for centuries. Also, there may be other adventurers or treasure hunters who are also exploring the temple. They could either be friends or foes to Harry. Additionally, he might encounter descendants of the Aztec people who still hold some knowledge of the temple's magic and secrets, and they could either assist him or try to stop him depending on their motives.
There could be a group of students who are known for their pranks in the fifth house. Harry would probably cross paths with them and might either get involved in their antics or try to stop them. Another possibility is that he meets a shy student who has some special abilities but is too afraid to show them. Harry could be the one to encourage this student to come out of their shell.