My name is Zach Santos. I am a higher education student pursuing Music/Sound for Visual Media, so I will tackle this from my perspective…
– Should propose the music to some record label or is it too late?
I feel that branding yourself can be more important than proposing the music to a record label. I believe owning my work and taking it to the appropriate licensing procedure is the best way to go about it. There is a way to increase revenue without the big labels.
– Which platform would be best? Bandcamp vs CdBaby, Soundcloud vs Youtube… Steam is also an option.
As long as your audio is iconic to the game industry and it’s audience, I feel as if you can do research on which platform will benefit you most.
– Royalties: are there any involved? I’m currently registered to BMI but I didn’t deposit the music tracks there.
I would prioritize this task ASAP for reassurance against any infringement.
– Incomes: are there conventions about the split between composer/dev company/publisher?
I hope that there is another way for you to make income with your audio without letting the developer own the asset.