Yang Xiao Long could be a key character. Her brash and powerful fighting style might be pitted against the kind of foes from the Man of Steel universe. And Weiss Schnee, with her family's influence and her own ice - based powers, could also be in the spotlight. She might have to use her skills in a different context, perhaps in a more technology - heavy and super - powered environment like in Man of Steel.
Clark Kent, when he's not being Superman, could be an interesting focus. His normal life and how it intersects with the RWBY characters' lives at Beacon Academy or elsewhere in the RWBY world could be explored. Blake Belladonna is another likely candidate. Her stealth and agility could be valuable assets in a world filled with powerful beings like in Man of Steel, and her own backstory could add depth to the fanfiction.
Ruby is a likely candidate. She's already a skilled fighter with her scythe, and her eagerness to learn new techniques would make her adapt well to Santoryu. Her speed and agility could be enhanced with the three - sword style.
Ruby is a likely winner. She has her powerful scythe, great speed, and strong leadership skills. Her ability to quickly analyze a situation in battle gives her an edge. Weiss also has a good chance. With her Glyphs and powerful summoning abilities, she can control the battlefield. Blake is another one. Her speed and shadow - cloning ability make her a tough opponent. And Yang with her super strength and ability to take a hit and then counterattack fiercely could also be a top contender.
I think Santana would be a key character. She has such a strong personality and her development from a bully to a more empathetic person could continue in the future story. Brittany might also be in the spotlight as she's always been a bit of an enigma and her relationship with Santana could be explored further. Additionally, Mr. Schuester could be important as he could be the guiding figure for the new generation of glee clubbers or dealing with his own post - glee club life.
Harry Potter himself is a likely candidate. He has endured so much throughout his life, from the death of his parents to the constant battles against Voldemort. Fanfiction could explore his post - war trauma and how he tries to lead a normal life.
Tony Stark is a likely focus. His intelligence and experience with technology, especially time - travel technology in the movies, make him a central figure. He could be the one to figure out the mechanics of time travel and lead the Avengers in their time - traveling adventures.
Tony Stark is likely to be a focus. His flamboyant and playboy - like personality could lead to some really interesting scenarios when affected by a love potion. He might make grand gestures towards someone he wouldn't normally be interested in. Another likely character is Natasha Romanoff. Her complex past and guarded nature could create a great contrast when the love potion breaks down her walls.
Ruby is an obvious choice as she has that lead - character feel. Her naivete and determination are traits that can be paralleled to Dorothy. She would be the one to lead the group through the strange world of Oz.
Naruto and Ruby are very likely to interact. Ruby is the main character in RWBY, and Naruto being the central figure in his own story, their paths would surely cross. Ruby's enthusiasm for combat and her leadership qualities could make for an interesting dynamic with Naruto's determination and his own brand of leadership. Also, Weiss could interact with Naruto. Given Weiss's strict upbringing and her proficiency in combat, her reaction to Naruto's unorthodox ninja techniques would be fascinating.
I think Weiss could also be central. She comes from a powerful family and has a lot of influence. In a story about watching the future, her knowledge of politics and her strategic thinking could play a big role. Also, her relationship with the other characters, especially Ruby, would be important in how they all react to what they see in the future. Blake might also be central as she has her own complex backstory and her views on the relationship between humans and Faunus could be greatly affected by seeing the future.
Team RWBY is definitely crucial. Ruby with her leadership skills and determination, Weiss with her family connections and combat abilities, Blake with her knowledge of the Faunus situation which could be relevant in the post - breach chaos, and Yang with her strength. Ozpin also plays a major role as he has the knowledge and experience to guide the rebuilding process.