In the meantime, I hacked together 
a way to get Sailfish OS notifications to my Pebble paired via AppSupport.
I don’t have a release-ready version yet, as I’d like to do some testing first - once I get my test device back. 
If any developers want to give it a try:
https://github.com/dscheinah/harbour-rockbridge
Unfortunately, it currently only works with Gadgetbridge, as I couldn’t find a corresponding Intent API for the official new Pebble app.