Actually, nevermind. I realized I don't need to find their hair color because you can easily change it with FEFTwiddler.
You seem to be misunderstanding something, so let me clear it up for you.
The hair color that shows up in the AID will
ONLY AFFECT THE 3D MODEL'S HAIR COLOR, it has nothing to do with the hair color you find in FEFTwiddler or the Hair Color that passes down, not even the sprite's hair color.
The one that controls that is set on the character's FID.
FIDs are easier to understand, unlike AIDs, they're all 0x48 in size, and again, like the AIDs, the last 4 bytes are the hair color.
The Hair color listed here is the one that actually matters.
For people static hair colors, like parents, this hex value doesn't do much at all, it's just the color that their children will inherit.
However, for Children, this determines the Hair color in sprites, in the AID, map sprites, and My Room model (MyRoom doesn't even read the hair color from the Children units, it actually takes the pointer to their variable parent and reads the hair color hex from the parent).
FID blocks are 2 blocks per character, the first block should start with a pointer to a FSID_ST_ label and the following block should start with a pointer to FSID_BU_
I managed to make a new FID entry in this file (back when I was doing Awakening Trio), I had actually fully added Lissa, made a new AID in ROM3, made a new FID entry for her, and also made a new block for her in GameData, but couldn't get her voice to work since it was a standalone BCSAR file.
The amount of effort I had to go through is really not worth replicating though.