I really don't think it would have to be censored. They can handle it like Detective Pikachu game because R was basically the game as the Shadow Pokemon. And we have already seen a version of Shadow Pokemon used by Team Rocket in the Lugia Arc of the Whirl Islands in Johto. Besides, they have done extremly well with mini series. They didn't hold back on the fact that Team Rocket killed Maraowak in Origins. And Ash literally being drained of his life and energy in XY Saga. Even the newer web series Hisuian Snow is really dark.
And saying Pikachu would just touch one... you do realize Ash probably wouldn't be in this anime right? Pikachu hasn't been getting the special treatment it once did. And outside of the main anime, Pikachu is near no existent.
As for having an anime with it. I also think it would probably be 4 to 8 episodes on the internet. They would have to cover the main detail. Wes stealing and then saving Rui. I think it could easily be condensed into a handful of episodes. I don't remember Gale of Darkness too much since I never finished that game.