I'm planning to rework each and every single partners' respective pages. Full details in my blog post:
I'll be reading any feedback in the comments below as well! The changes are not immediate but I've already have some stuff planned out.
I don't know if it's song or partner. But I realized you don't have to clear "fracture ray" in EVERY difficulty to unlock the hikari (zero). One difficulty is enough.
What do you think?