So was I the only one who thought 'Why is that S floating there?' rather than having a nostalgia trip? Mind you I had a Commodore Amiga, rather than a SNES so that might have been it.
The "floating S" is a sound trigger that let's you hear a waterfall in the near background. The "P"s are effects (splashing water). Ingame it will look like this:
About the mod:
Sorry, I'm not continuing as of now because there is no way I can inform myself about any function. There is no documentation for the editor and trial and error (testing every function until it works) takes way too much time.