Is it possible with Broodwar 1.16.1? Or Remastered?

What I care about most is individual music playlist for each faction.
Faction selection from the menue would be nice, but I am fine with workarounds like a starting building having 3+ morphing possibilities.

Music is notoriously hardcoded, and it has issues connected with campaigns that you need to be aware of if you're replacing built-in campaigns. I guess only Neiv can shed the light on the issue in any real detail.

Actually there is an easy way to do this. You will need to create a scm file and import all the songs you want, next use a trigger always and the play wave to the first song you want. Next you will make elapsed time triggers to play each wave file after that. You will need to calculate the number of seconds of each song, do this by using multiplying the number of minutes by 60.

Here's the framework
Song 1: (2 minutes) × 60 = 120
Song 2: (1 minute) × 60 + 120 = 180
Song 3: (3 minutes) × 60 + 180 = 360.
Do this so on and so forth as well as looping your playlist so it never stops playing your songs.

Doing this for specific races will require you to play multi-player (by yourself) and select yourself as either player 1 2 or 3
You will need to program the playlist for each slot that you will set a race for.

1 min song would be aprox 720 death counters if he would be using that