I am working on a Pokemon/Harry Potter crossover. Is there anyone else that knows about and is a fan of both series? I would like another co author along with my current, While Alex is working with me on writing the stories, I need someone who could add detail and other improvements on it. If you are willing to help, I would appreciate it, I need someone who has alot of time to help. Thank you.
I'm not sure if you're going to get a co-author asking this way. This forum really isn't open to the idea of co-authors for a variety of reasons. Your situation is even more peculiar because it's going to be three people working together, and the writing styles might flow and it would seem forced.
What you can do is see if you can find one or more beta readers who are familiar with the fandoms, so you can ask questions and see if enough details are included. You'll still get help, but it'll be easier to find rather than looking for another co-author. I believe more people are willing to beta than co-write.
Whatever happens, I hope you find the advice you need, and good luck!