Would either recommend mapping the intro on: Kantan, Oni, Inner Oni. Or omiting it from the guest difficulties for set consistency. Please verify with difficulty owners that you are okay'd to omit... if you decide to take this suggestion in that direction.
here's the thing, the intro is only mapped on top diff with Sotarks's set. I can follow that idea.
https://osu.ppy.sh/community/forums/topics/131540?n=1
You can copy timing points and their audio without changing hit sounds (which would re-color in taiko) I recommend exporting a version of the set as backup before messing with it though
I do have to question why slider velocity is set to 1.72 vs 1.4 or 1.6? And not all tags are shared between all diffs, make sure to rectify this!