Any idea on how I can get to the files TO edit them?
If no one has written an application yet, you'll probably have to write one yourself.

I imagine the text in FF6 is compressed, so you could dump the battle script, decompress it, edit it, recompress it, and reinsert it. Not that I know exactly how to do that... Just, if you don't know anything about this kind of stuff and no one has written an app, it's going to be rather difficult. :-/