Best answer by melvimbe
As for the Spotify issue, have you setup the Spotify account within the Sonos app? The account needs to be setup in Alexa and Sonos to work properly. It sounds like you did so, but the scenario your describing makes it sound like it's not.
When you say that you're using the iphone to start spotify, which app are you using? Sonos, Spotify, Alexa? Are you using airplay?
Have you enabled the Sonos smartskill? If not you definitely need to do that.