As of writing, there is currently no known way to edit songs. I have no clue what format they're in other than they use AKAO similar to FF7. I also have no clue how to replace sounds in the sound files.

As for extracting sounds that are used to play the AKAO files, it is incredibly easy. The tool that I use is vgmtrans. Sound files are INSTRXXX.ALL files. Just drag and drop the file into the window, right-click on the sound file on the left side, and export everything to WAV. It's that easy. 

I'll update this thread as I learn more about stuff