Obviously, Summer is a main character. Her actions and experiences drive the story in most cases.
Ruby could also be a main character in some of these fanfictions. Since Summer is her mother, Ruby might be on a journey to discover more about her mother through memories or other means. So Ruby's perspective and her growth related to Summer are important parts.
In addition, villains from the RWBY universe could also be main characters in this fanfiction. If Summer's resurrection is part of some grand plan by Salem, for example, Salem herself or her minions could play important roles. They might try to manipulate Summer or use her for their own evil purposes. And this would lead to many conflicts and battles in the fanfiction as Team RWBY and their allies try to protect Summer and stop the villains.
Most likely, Summer herself would be a main character. Ruby would also be very important as Summer is her mother. Then there would probably be other members of Team RWBY like Weiss, Blake, and Yang, as they are likely to be involved in the story due to their connection to Ruby.
Obviously, Summer and Naruto would be the main focuses. Summer, with her skills and backstory from RWBY, would bring her own set of abilities and relationships to the story. Naruto, on the other hand, is full of energy and has his powerful ninja techniques. Their interactions would be central to the fanfiction.
In RWBY Summer Lives fanfiction, often there are stories that focus on Summer's relationships. It could be her relationship with her team members. How she trained Ruby, or the bond she had with Yang's mother. These relationship - centered stories can add a lot of depth to the character of Summer.
Well, of course, the summer dragon itself is a main character. It could be a majestic and powerful being with a kind heart. There might also be a young protagonist, perhaps a wizard - in - training who stumbles upon the dragon's existence and forms a bond with it.
Often, there's a young protagonist, could be a boy or a girl, who is at the center of the story. The dragon is of course a main character too. It might also have a wise old wizard or mentor figure who guides the young protagonist in their journey with the dragon.
I'm not sure specifically as there are many possible interpretations in fanfiction. It could still feature Ruby, Weiss, Blake, and Yang as main characters, but with a plot centered around dilation. For example, Ruby might be the one to first notice something strange related to dilation and lead the team to investigate.
I don't know for sure without reading it, but it could feature the main RWBY characters like Ruby, Weiss, Blake, and Yang. Since it's a fanfiction, there might also be an original character who is the'stray' that the story focuses on, and this new character could interact with the main RWBY quartet.
Obviously, Cliffjumper is one of the main characters. In most of these fanfictions, he is the one bringing his unique set of skills and personality into the RWBY universe. Then there are the main RWBY characters like Ruby, Weiss, Blake, and Yang. Ruby with her leadership and scythe - fighting skills, Weiss with her Glyphs and swordplay, Blake's stealth and katana - using abilities, and Yang's brawler - like combat style often interact with Cliffjumper in different ways in the fanfictions.
In most 'rwby yellowbeard fanfiction', Yellowbeard takes center stage. He's the one with the unique look and backstory. But the RWBY girls are essential too. Ruby with her leadership skills, Weiss with her grace and combat abilities, Blake with her stealth, and Yang with her strength. There may also be other characters from the RWBY universe that pop up, like Professor Ozpin or Qrow Branwen, who might interact with Yellowbeard in different scenarios.