Obviously, Keith and Lance would be the main characters. They are the ones directly related to the concept of Keith wearing Lance's jacket. Other characters from their team or universe could also be included, like Shiro who might notice the jacket exchange and have some sort of reaction to it, or Pidge who could make some teasing comments.
Keith and Lance are the central figures. Keith, who is wearing the jacket, and Lance, the owner of the jacket. However, the story could also introduce new characters. For example, a character from Lance's past who gave him the jacket and when they see Keith wearing it, it stirs up old memories for Lance. Or perhaps an enemy who mistakes Keith for Lance because of the jacket and attacks him, leading to an action - packed sequence in the fanfiction.
Well, it could be a story about Keith borrowing Lance's jacket by mistake. Then, Lance notices and is initially a bit annoyed but as they interact more because of the jacket situation, they start to understand each other better and become closer friends.
Obviously, Keith and Lance are main characters. Keith is the one going to meet Lance's family.
Obviously, Keith himself in his baby form would be a main character. His friends like Lance, Pidge, Hunk, and Shiro would also be main characters as they are the ones who would most likely be taking care of him or trying to find a cure. Maybe Allura and Coran could also be important characters, helping out with their knowledge of Altean technology or magic that might be related to Keith's transformation.
He might be polite but a bit guarded at first.
His Pikachu would definitely be a main character still. Pikachu would be there by Ash's side as he discovers this new relationship. Maybe Brock could also be an important character. Brock, being Ash's friend, could offer advice and support. He might be the one to help Ash make sense of it all, and also be there to keep Ash's spirits up if things get tough.
Obviously, Hermione herself would be the central character. Harry and Ron would likely be important secondary characters. They could provide the reactions and banter that are typical of their friendship. Maybe Luna Lovegood could also be involved. She might be the one who encourages Hermione to be more adventurous with her clothing choice and be supportive when others are a bit judgmental.
One common theme is friendship. Their relationship often starts as a rivalry but gradually turns into a deep friendship in many fanfictions. For example, in stories like 'From Rivals to Allies', their journey of understanding and supporting each other is the central focus.
A lot of the fanfictions about their kiss also explore the reactions of the other characters in the Voltron team. Some might be supportive, while others could be initially shocked or confused. The kiss can also be a symbol of a new era in the team's dynamics, as Keith and Lance's relationship changes. It can lead to interesting storylines about how the team adapts to this new development.
Teamwork is also a big theme. In many fanfictions, they have to work together as part of a team and their relationship is strengthened through that. And there's the theme of sacrifice, where they might be willing to sacrifice for each other.
Lance's family might be really welcoming. They could see that Keith is an important part of Lance's life and embrace him right away.