In the superhero story that I'm currently writing, I have two protagonists, one of them is a high school girl by the name of Mercedes Kendrick, and the other is Agent Orion Anderson who works for the FBI's fictional mutant affairs department. I've been writing a good bit for both of them and I'm currently on Chapter 9, but they haven't interacted yet. Orion basically takes down mutant criminals who commit federal crimes and things like an FBI agent normally would, only in a fictional setting with mutants. The reason they haven't interacted is because Mercedes hasn't donned her costume and started her hero career yet. She's about to which will put her on Orion's radar, because in my story setting using superhuman abilities as a vigilante is illegal, according to part of the backstory it has been since 1977. Is this too late into the story to have them interact? The thing is Orion's plot doesn't just revolve around Mercedes, he is dealing with other things in the story as well, so I'm also wondering if the two plots aren't interactive enough, because it's almost like I'm telling two stories at once.
I personally don't think it is, as long as they're going to interact at some point, which, to my understanding, is what you're going to write next. There are a lot of books where it can feel like that, some good, some bad, one example being The Thousandth Floor by Katherine McGee. The characters do all interact at varying points, but they all have plots of their own that leads them separate ways, too. Sometimes it worked, and sometimes it felt like too much. So it can be a hard line to stay on the right side of. I think it may depend on how much they interact: it's okay for them to go off and do things on their own, but if their actions never impact each other (although surely they will, if Orion will be essentially hunting Mercedes down) then it might seem odd.
My book has parallel stories interwoven (same protagonist, different timeframes). You can write each story separately then see how to integrate or intertwine them later. One thing I found from my critique group, how you open the story is going to be critical given you have two stories to introduce. Be prepared to kill a few darlings.
I think it's totally fine. I think that it might be fun to have him be aware of her and maybe even meet her, after the reader knows both characters well but before the formal meeting, if that would be plausible (are her abilities on anybody's radar?). But I don't think it's mandatory.
No, they live in the same city, but due to age and occupation differences, they have no reason to interact until she starts doing the superhero bit.
Maybe before they interact you can still link them together through small things? For example: in one chapter, Mackenzie is walking to school with her earphones in, listening to Band XYZ. In the next chapter, Orion gets in his car and drives somewhere, listening to Band XYZ. They haven't met yet, but now there's a little thing tying them together that's almost acknowledging the other side of the story. Or they both enter the same coffee shop at the same time but don't interact, yet we can see they're both there and so we're desperately waiting for them to meet, and also experiencing dramatic irony when their paths uncross themselves again because we know they must have something to do with one another, but they don't seem to know it yet. Or Mackenzie goes somewhere, leaves, and Orion arrives five minutes later...and now we experience the frustration that they've missed each other and read on eagerly for the moment when they will both be in the same place and they will both interact.
