I think I'm going to take a stab and share a link to this concept I made for a revised Conquest run since last year. It's a complete overhaul of Fire Emblem Conquest with Revelations attached to the near end. I was planning to make a revised Birthright path, too, but I'm just one person, so I had to scale things back a lot. My intent with this really long project is, like many others, to improve Fates' plot and flesh out the world the games take place in. I never really had a name for it, but I guess I'll call it "I As Future Kings" because that's the name of the blog anyways.
I don't have the time and resources to make something nearly as polished as editing those really nicely edited videos and full character portraits for this AU, nor do I have the time to write fully written fanfiction. So I've taken to scripting scenes like those text LPs with talking sprites and drawing a few comics wherever I can. I've been rather hesitant about plugging it to the community because I wanted to make enough content to show people on hand rather than just saying I'm going to make one and losing the motivation to commit.
I made a Tumblr blog with a meticulously tagging system for any content and answered questions. On the same site, I've made two timelines, one for the past and the present. Most of the written "scripts" and comics have been compiled on a single fic on AO3 called "As Dark Comes the Night". I'm slowly but surely trying to archive the editorials, reader Q&A, and worldbuilding post on the AO3 series under the same name as the blog. In case anyone is wondering a brief list potential clinchers or deal breakers (plus some spoilers):
I'm more than happy to answer any questions.
edit: I needed to refine that list of bullets