Sorry Jim for the confusion and I certainly relate because we all have to start somewhere. So for clarification when I say “smartapp” I am referring to applications that run with the ST environment only. The term app would refer to a mobile phone app that runs iOS/Android (such as the ST mobile app). Yes, the Samsung Multiroom is an iOS/Android app that is completely separate from the ST mobile app. Multiroom will operate the music independently from ST. I am not aware of ST smartapp that ST mobile app can play your music library say like a standalone Multiroom app can. I would download the Samsung Multiroom app to your phone to play with it and see what it can do.
Smart Lighting on the other hand, is a smartapp that runs within ST environment such that you can configure it to monitor your motion sensor and anytime it senses that it is active it can than turn on your kitchen lights and then after a pre-determined amount of time say 60 minutes would then turn off the kitchen lights again. You fibaro will all be controlled from within the ST mobile app. FYI: This is not totally off topic but what lots of people do though is install the smartapp called SmartTiles by @625alex @tgauchat . SmartTiles basically allows you to use a browser interface to monitor/control your ST system from a standalone device like a tablet, PC, etc.