Because I saw someone getting hate online for writing a spinoff of SIX about the ladies in waiting, threatening to report the author for illegal acts and copyright infringement to Toby Marlow and Lucy Moss, I decided to read up on copyright law and fair use so I could use the platforms I have. Also, go look up moan-jeutas on tumblr. She's the author of the spinoff and a lot of other LIW-centric stories that are really great.
So, to be clear, as long as she doesn't include quotes and music from SIX, she is absolutely not infringing on Toby and Lucy's property. The ladies in waiting were real people, and therefore cannot be considered original characters. Yes, the concept of a concert-style show about historical figures is something they came up with and - as far as I know - is unique. But it's unlikely that it will ever be the only show like that. Also, the idea of taking historical figures and setting their stories to modern styles of music is not unique, being seen in shows like Hamilton and Bloody Bloody Andrew Jackson.
Also, this script is not for monetary gain. She is a fan fiction author. This is what she does. While technically, most fan fiction breaks the law by using previously existing characters and branching if of previously existing stories, nobody really cares because the people writing it are not trying to get paid for it. The script in question is never even going to hut the stage. Also, once again, the ladies in waiting are real people. There is no copyright law on the existence of a human being. I never thought I'd have to say that, but here we are. The only connection to six in the screenshots that have been released are the opening where the queens leave the stage and references to the queens having designated colors. Other than this, it's about the ladies in waiting and nobody else. Yes, the queens are mentioned because the stories are about their ladies in waiting, but once again, copywriter law does not apply to real people. Only original characters.
So, basic summary, technically most fan fiction breaks copyright law but nobody cares, and so long as it only features original characters or historical figures, you don't quote anyone, and you don't directly copy literally an entire storyline, there's nothing that can legally be done against you.
So guess what, you can't write a pop concert about the six wives if Henry VI, but you can for literally anyone else.
