The SNES sound files are SPC files. You can get the entire soundtrack from Super Castlevania IV and pretty much any other SNES game from Zophar. The soundtracks come in a zip package of SPC files and run around 100 KB, so easily downloadable. The Zophar site also has a wide range of SPC players and plug-ins, so you can pretty much choose your favorite way to do things there.
Anyway, as someone who played the heck out of this game, I noticed no difference between playing the original game and what came out of my computer's speakers.
I have 95% of the sound editing done. I think I might try out the SOTN score - it's been a while since I've listened to it, though. Some of the music I think would fit very well, but some I think just won't, but since people are interested, I am willing to try it out. I'll keep you posted.
As a side note, I have been working with a 800 MB mpeg file from archive.org. Personally, I think the quality is perfectly fine for this project - the intention here isn't necessarily to have the end-all, be-all version of Nosferatu, but rather a nice side interest. I think 800 MB makes it easier for people to check out, as opposed to a 4 GB standard-DVD-sized project, but that's just me. Also, I really wish that I had the German version to be working with, but I just don't. Anyway, I don't know where I'm going with all this, but I figured it would be good to mention the quality issue at least somewhere.
The Kino DVD version is supposed to be the best from what I've read, but I've never seen it, so I can't personally vouch for it. I'm sure it would be great to see this (these) soundtrack(s) hooked up to that, but again, I'm not intending this to be the ultimate version, but just an optional version.
Let me know what you guys think. Thanks for the interest! I was worried no one would care.