When commissioning something like a character theme, what resources do you provide the composer to work with? For example, do you send over Ajna's profile or a bio of her personality to fit with the music? Maybe more of just a general genre/cultural reference?
Generally music falls into two categories for us: environmental and cinematic.
For environmental stuff, we mostly provide art, a story summary for that region, and some keywords. In almost all cases, he's nailed these on the first try. But in the cases where he hasn't, we'll follow up with some references to help guide him towards the feeling we're looking for.
For cinematic / character stuff, which is more emotionally ambiguous and difficult to describe, we start out with reference music, as well as story summaries and keywords.
And for what it's worth, virtually all of the "misses" are still great pieces of music, so we find other uses for them. For example, one track for a particular sequence in the game didn't fit what we were looking for, but made a great general tension / excitment / shit happening track. So we kept that for that purpose, and then provided additional reference to get what we were looking for on the other one.
In addition to this, I walked Kikuta through the entire story over a lovely dinner when I was in Tokyo for TGS last year, so he'd have a sense of what we were looking for. And we also sent over a translated outline of the entire story after that.
He promised that the music at the end would make people cry.
For Ajna's theme in particular, it was always envisioned as being the same theme as the main theme, just as a more personal, quiet take on it. So we started with reference for the main theme, and then once we got that done, we had him prepare the Ajna theme "remix."
Oh god how much I hate you, I mostly listen to battle themes when I run and I'm running out of them at the moment

throw us something later.
Because each region has its own exploration and battle theme, this game will have a LOT of battle music. Not to mention boss music. So you should have quite the playlist for your running. Estimating around 15-20 tracks that would fit that description?
Awesome. Can you answer how much he's written so far?
I need to actually sit down and add all this up, but I'd estimate that we've probably got around an hour of music right now.