I found that SPS supports custom vertex functions, and although it doesn’t support bones, one can grab the position of the animated mesh (Get vertex position of animated mesh) and pump it via SPS.updateParticleVertex.
sample PG here: Babylon.js Playground
I have not extensively tested it since I do not need large particle count. If there was an easier way to avoid recomputing the positions of the animated mesh, I think the perf would improve. So I guess food for thought or for some coder better than me. 
Which means this feature request is not really needed anymore, which is a good thing. Feel free to close, thank you!!! 