The trouble will be that music does not necessarily work the way you are imagining.
Your plugins for music players are basically emulators without the graphical aspects. The NSF being a slightly tweaked ROM with the audio aspect described in a certain way and with the graphics and whatnot stripped out. Some later devices can have it a bit easier as they are basically a software format with software defined wave samples but often are still emulators, or still lean into emulator derived playback if there are some nice features custom to the underlying hardware.
This is to say the older devices had several nice custom chips (occasionally governed by their own processor, though most will be thinking megadrive/genesis for that one), possibly another wedged on the game cart itself to give that little bit extra to play with ( https://wiki.nesdev.com/w/index.php/List_of_mappers
, see those mentioning audio, though SNES and N64 tended to be more about graphical or clocks or controllers or something extra on the processing than audio, though in doing so it would free up resources to have more fun with audio).
Tracks were not necessarily (some were though) basically a bit of glorified sheet music saying play this sample for this long as much as potentially long string of assembly.
For the N64, though it started to resemble the software defined stuff of today, they still had that bit of custom aspect. I was watching a video stream once with some former Rare devs detailing development and basically dev commentary on Conker's Bad Fur day. One point they mentioned in a game having two tracks play simultaneously so when the player crossed a transition point they would have the track fade into the other right where it would be had the player been there all along. That said end stage boss triggering musical double time or maybe looping a smaller section round and round a few times is something you will probably find examples of.
Back to the older devices then it was also not really like the GBA or DS wherein there is a major software format that the vast vast majority of games use, so much so we note the exceptions, and said exceptions are usually "plain wave", "well known PC format", "well known game format" or minor header on each of those. The audio engineers/game musicians of the day were often highly competent programmers in their own right and usually custom made one for each game, or maybe custom made one games in the same franchise (or possibly same dev/pub) would use, though potentially developed or twisted a bit to suit purposes between different games.
This is not to say you can't do something, and maybe your limited selection could have it more boring and basic (though most of those being flagship titles with several noted examples of devs of them pushing the boat out a bit in terms of what the hardware was normally expected to to rather than cartoon tie in games that is not a bet I would take). However I would not be suggesting a hex editor for this (saving that you compare and contrast your already made rips with the original ROM) and that you have one is assumed and largely immaterial. You will then largely be getting down and dirty with a debugging emulator and hardware documentation of the, maybe if you are lucky a description of the audio setup from that game from a hacker that came before you or an interview with the audio programmer in the years since.
This is also why audio hacks on anything older than the GBA that was not on a CD or maybe Amiga (various tracker formats coming out/rising up in that world) are so rare, generally considered one of the more difficult aspects of it all, and any tools tend to focus on specific games (and are anything but import-export or basically a tracker program you can tweak).