What you have here is something very complex and won't be a simple project to pull off. I wanted to compliment you on your post and how much thought you've put into this and to tell you that, most likely, this story will turn out best if you write it yourself.
There was a post here recently about someone wanting to commission a story as well. In the end of the conversation, they decided that those who gave them the advice I'm giving you now (myself included) were right. You know your ideas best, and if someone writes a story based on that and doesn't fulfill all of those expectations, you will not only lose the idea, but you may also be disappointed.
This idea did intrigue me, and I think I could come up with a story to fill it. However, Limerance is taking up all of my time and focus at the moment, so I won't be able to do this until much later. By then, someone else will probably have taken you up on the offer
I also wanted to comment on #3 of your list. Focusing just on the main character isn't necessarily bad writing. It can very well be a stylistic choice and has been done in many a bestselling book or even series. I will agree that the other side characters must be more than one dimensional. Heroes always need support, and that support must also be interesting if the story line is to be believable.
Thank you for generously posting this idea. I wish you the best of luck with this and I think that a very interesting story could come of it