ok i thought it had to in the main menu, i tried quickly peaking at the FSB Audiofiles all i can tell its in a FSB5 format :/ no luck playing/converting.
The audio files are very weird. Although, using someone's sample template from the World of Tanks forum in FMOD designer,
I got the main menu music to change. That's as far as I went with audio, because I don't understand how to use FMOD Studio or how the files work. I feel like I got really lucky with this, since the template had a "main_menu" section within the unbuild file, so I just deleted everything else, build and renamed it, and it worked.
Though, it seems like the FSB files that the game uses are a different form of FSB5, it seems to accept just anything that's FSB. (I think. I didn't think to analyze the FSB I built off the template.)
With the 3dst textures, I got most of the files to load except the ones in images\gui\backgrounds and the logo files in the gui folder. Everything else worked just fine, and could be modified, though it seems the uvs are upside down from what Ohana displays. (I assume that's just a normal thing though, and not related to Ohana.)
The only other things I did was
replace one of the skins with my JE skin, and
play with the credits file. I haven't really messed with the game since.
I think it's kind of strange that they would use such different formats than most other 3DS games do. I was really hoping it'd be way easier to modify than it is. :/