Is there support for using Alexa to play local Sonos playlists, or is support limited to the listed online services?
Best answer by Ryan S
From the announcement post here
You can use Alexa to start playing from Amazon Music, Amazon Music Unlimited, Pandora, iHeartRadio, SiriusXM, TuneIn Radio, and we’re working to bring Spotify controls in the future too.
Also, any Alexa device on your account can use basic controls, such as play, pause, volume, and skip, on your Sonos players. This works for all services and music on Sonos, started through the Sonos app.