Oh hey, you must be the guy who asked a question about changing the palettes in DK in the comments from my rainbow DK hack video. Did you get that worked out? My reply was a bit convoluted because the whole process is a bit convoluted.. but you can use MAME to view the color palette - so you could edit the two palette ROMs in a hex editor then have a look to in MAME to see which bytes change which colors changes.
Changing the music is probably doing to be insanely involved. You'd have to find or make a disassembly of the sound CPU code and then rewrite parts of it, make new music tables.. I'm not aware of anyone having tinkered with that side of DK's code.