Searching an audio player (+flow) for streams / local files

General
2

Is there a way to fast-foward / rewind a mp3 song while playing with PlaySound node?

If you are talking about node-red-contrib-play-sound it is based on nodejs play-sound. It play sounds by shelling out to one of the available audio players so it would depend on the abilities of the player you were using.

As for the rest, looks like your going to have to do some digging and testing. I did provide a music player project I made you could use as a starting point.