I think Luna Lovegood could also be included. Her unique perspective and knowledge of the magical world would add an interesting element to the road trip. She might lead them to discover some really strange and wonderful things.
Obviously, Harry Potter himself is a likely hero. His experience in fighting Voldemort has given him the skills and courage to face new apocalyptic threats. Hermione Granger is also a strong candidate. Her intelligence and vast knowledge of magic would be invaluable in trying to solve the problems causing the apocalypse. Ron Weasley, with his loyalty and ability to think on his feet, would be right there beside them, fighting against whatever doom is approaching.
Yoko from Gurren Lagann and Hermione Granger could be paired. Yoko is a strong and independent female character, and Hermione is brilliant and resourceful. They could team up to face challenges, with Yoko providing her combat skills and Hermione her vast knowledge of magic. Their combination could be a force to be reckoned with in the fanfic.
Luna and Neville would be another possible pair. They are both somewhat outcasts in their own ways in the Harry Potter world. In the fanfic, when the bottle lands on them, it could lead to a really sweet and heartwarming moment. They could bond over their shared experiences and unique perspectives on magic, and perhaps develop a deeper relationship.
Ron and Uryu might be paired. Ron has his own insecurities but also his moments of great courage, much like Uryu. They could bond over their skills in combat, Ron with his magic and Uryu with his Quincy powers.
Obviously, Harry Potter and Clark Kent would interact a lot. They are both iconic characters in their own universes. Clark, with his superpowers, would be curious about Harry's magic, and Harry would be interested in Clark's abilities. Also, Hermione Granger, if she somehow also ends up in Smallville, would likely interact with Chloe Sullivan. They are both intelligent and inquisitive, so they could bond over solving mysteries or studying the differences between their two worlds.
Hermione is a very likely candidate. With her intelligence, she could easily start a business. For example, she might open a library - like establishment but with rare and restricted magical books that she has managed to collect through her research. She could charge a membership fee for witches and wizards to access these valuable resources.
Obviously, Harry Potter himself would be a likely participant. He's always up for a challenge and has great courage. Ron Weasley might also join in. He may not be as naturally talented as Harry in some areas, but he's always eager to prove himself. Hermione Granger could participate too. She would approach it with her typical studious attitude, researching all the proper techniques and spells related to archery. Neville Longbottom could be another character. He has grown a lot in confidence and his skills with plants could potentially give him an edge if there are any plant - related aspects to the archery tournament, like using arrows made from special magical plants.
Voldemort would also be a key character. His obsession with immortality and his actions that led to many deaths in the series are fundamental to the theme of life and death. In a crossover, he could be pitted against new threats or forces that have different views on death, which would make for an interesting story.
I think the members of Dumbledore's Army could also play this game. It would be a way for them to bond in a more light - hearted way outside of their usual training. Ginny, Luna, and Neville would all be great candidates. It could be a moment of relaxation for them in the midst of all the chaos at Hogwarts during the darker times.
Fred and George Weasley would also be great at it. They are creative and always up for some fun and mischief. They would see Beyblading as a new and exciting way to cause a stir at Hogwarts. They would likely modify their Beyblades with some of their magical inventions, like adding a spell to make their Beyblades move faster or change direction suddenly.