One popular plot idea could be the OC being a new student at Max's school. They start off on the wrong foot, like the OC accidentally getting Max in trouble. But as time goes on, they discover they have a lot in common, such as a shared love for pranks. Another idea is that the OC has a special power that Max is intrigued by. They end up teaming up to take on a common enemy in the world of superheroes and villains. It could also be that the OC is from a different dimension and Max has to help them get back home, during which they form a deep bond.
First, give the OC a distinct personality. For example, if Max is more of a rebel, the OC could be a bit more of a rule - follower to create an interesting dynamic. Second, think about their backstory. Maybe they grew up in a different environment that shaped their views. For instance, if they grew up in a strict military family, it would affect how they interact with Max. Third, their appearance should also match their personality. If they're shy, they might have a more reserved style of dressing. Also, consider their goals and dreams. If they want to be a famous scientist, it gives them something to strive for and can be a source of conflict or connection with Max.
There should be. Since 'Billy Thunderman' has a wide fan base, including younger viewers, many fans would write stories that are appropriate. These could involve things like Billy's school life, his relationships with his siblings in a positive and clean way, or his attempts to master his powers without any inappropriate content.
One popular theme is the development of his superpowers. Writers often explore how Billy further hones his skills and discovers new aspects of his powers.
Well, you'd have to look at the details and the source. If there are no claims of it being true or references to real people and events, it's likely not a true story. However, some elements within it might have roots in reality.