Hi,
I saw, that you removed alsa-plugins in early 2016. With snapcast we have an alsa-only addon which would need the alsa pulse plugin to output sound to pulseaudio. That would be the only way to have this addon send data to a bluetooth speaker.
I am currently trying to re-enable the old alsa-plugins package file, it seems to be working (build package worked, make image is still running).
Could you think about re-enabling it in general, or maybe as an addon?