Hermione Granger is also a likely character. Her intelligence and love for knowledge could lead her to discover a way to bridge the past and the future. She might use her Time - Turner knowledge or find some new magical method. And she could play a key role in helping past characters adapt to the future or vice versa.
Albus Dumbledore could be involved as well. He has a deep understanding of the past and a great influence on the future of the wizarding world. His wisdom could be used to guide both past and future characters in a situation where the past meets the future. Maybe he appears as a ghost or through some time - magic to give crucial advice.
Obviously, Harry Potter himself could be involved. He might be a mentor figure in the future, passing on his knowledge and experiences to the new generation. His children, if the fanfiction extends to that, would also be key characters. Hermione and Ron could also play important roles, perhaps as educators or as important figures in the wizarding government. Neville Longbottom could be involved too, maybe as a herbology expert who is helping to develop new magical plants for the future wizarding world.
Definitely the Weasley twins, Fred and George. They are known for their love of mischief and innovation. They would be all over the idea of street racing in the wizarding world. They could create all sorts of magical gadgets to use during the races. Another character could be Draco Malfoy. He would likely be a rival racer, using his family's wealth and influence to get the best magical racing equipment.
Harry himself is very likely to be involved. Given his many encounters with death, from facing Voldemort to losing loved ones, he has a deep connection to the concept. He would be exploring the aspect of death perhaps to gain more power to protect his friends and the wizarding world.
Definitely Torbjorn. Since he has a connection with Bastion in the original Overwatch lore, he would be a central character. Reinhardt could also be involved. His chivalrous nature might lead him to protect Bastion if he saw it was in trouble. And of course, Mercy. She's always there to heal and help, so if Bastion gets damaged during the story, she would be there to patch it up.
Lily Potter would also be involved. She was James' wife, and if James saw something in the future that affected their family, he would surely involve her. Also, Dumbledore might be in the story. He was always a key figure in the wizarding world, and James might seek his advice on what to do with his visions of the future.
Obviously, Harry, Hermione and Ron are the most likely. They are the main characters and are always together, so it's natural for them to be playing truth or dare. Neville could also be involved as he's their friend. And Ginny might join in too, especially as she gets older and becomes closer to the group.
Definitely Harry Potter himself. He's the central character in his own series, so it's likely he'd be involved in any crossover. Hermione Granger could also be a key character as she's smart and curious, and would be interested in learning about the 'Twilight' world. From 'Twilight', Edward Cullen is an obvious choice. His brooding nature and unique abilities would make for interesting interactions with the 'Harry Potter' characters. Also, Jacob Black could be involved, especially when it comes to the 'imprint' aspect as he has his own story arc related to that in 'Twilight'.
Probably Harry Potter and Edward Cullen. Since Edward is sort of the main character among the Cullens in a way, and Harry is the central figure in his world. They both have unique abilities and a sense of responsibility, so it makes sense for them to be the first to cross paths and start interacting.
Definitely Harry Potter and Finn Hudson. Harry is the hero in the wizarding world, and Finn is a key figure in the Glee club. They could bond over their leadership roles. Harry could teach Finn some magic tricks, and Finn could show Harry how to be more confident while performing in front of a large audience.
Harry and Ginny could also be involved. They are adventurous and in love. After the war, they might want to do something crazy and out - of - the - ordinary. A trip to Vegas for a wild wedding could be just the thing. Ginny might be the one to suggest it, thinking it would be a fun way to start their married life, and Harry would be all for it, seeing it as another exciting adventure.