I realize I was very inexperienced and didn't know much of Touhou in the first place, so I think I would rather start from the same situation as Touhou LostWord did (This means I will be starting from scratch and this timeline will be continuing from Wily Beast and Weakest Creature after the whole incident is resolved) and start the story from there.
Synopsis? Basically, Natsuki Shirogane, a regular human who had no 'Drive' got dropped into a cauldron back in the BlazBlue timeline by Hazama after being caught by the damn snake while trying to smuggle some top-secret info out. Somehow survives the Boundary, and enters a different Boundary entirely. Well, more will be shown later. I hope you understand.
I will be scrapping the FGO story as well, but I still plan on doing something along the lines of a Chaldea meets Gensokyo thing. Will I add BlazBlue elements into Gensokyo? No. I probably won't. It's a pain trying to get Seithr to work in what is essentially an Eastern Magic Wonderland filled with Youkai. And I realized that very quickly. Rather, Gensokyo will be Natsuki's home base from which he can go to different worlds. So yes, Natsuki will essentially be dimension hopping and solving some 'SINGULARITIES/INCIDENTS'.
I hope you will all enjoy the upcoming content.