Don't use original files!
Let me repeat that once more,
DON'T USE ORIGINAL FILES.
1/ First of all, they are copyrighted and you are not allowed to redistribute them or even modify them.
2/ Second of all, there are many different versions of them. Not all work on all platforms. Also they have different names, so if someone is using sounds from SOUND1/2.CAT they will not be able to use your sounds defined in SAMPLE1/2.CAT; and vice versa. In simple words, no matter what you do, it will not work for everyone!!
Also, music is not in the files you mentioned, only sounds... music is in completely different files, see:
https://www.ufopaedia.org/index.php/SOUND#Music_filesI already told you how to properly mod sounds and music in this post:
https://openxcom.org/forum/index.php/topic,7355.msg116238.html#msg116238To repeat myself:
1/ For sounds, create OGG or WAV files and add them to "extraSounds" ruleset under "BATTLE.CAT" for surface sounds and "BATTLE2.CAT" for underwater sounds. This is the only proper, consistent and working method of modding sounds in OpenXcom
2/ For vanilla music, you can replace it just by creating OGG files with proper names, see for example how it is done in Cydonia's Fall mod:
https://openxcom.org/download/extras/3/ Custom music (for example when you want a different custom music for a particular mission), should also be created as OGG file, then defined under "musics" ruleset and then used in alien deployment ruleset, or any other place which allows to define custom music
There are no other ways to do it correctly.Many mods already do that, download and check them for examples.