Icons: great. Just need to be white assets with no borders and no transparency.
Spinner: nope, it shouldn't do. Take a look at how Google do it in the Google+ app, or in the Google Play Music app.
Sidebar: cool. You could use a sidebar on the other side for notifications later.
Up button: it's usually used for going 'up' to the previous Activity, you're right, but in the past it's also been used for going back to the previous interactive element. Up to you whether you use it.
Silhouette: throw the icon in the Launcher Icon generator and it should spit out a silhouette'd icon ready for use in the app.
Icons: great. Just need to be white assets with no borders and no transparency.
Spinner: nope, it shouldn't do. Take a look at how Google do it in the Google+ app, or in the Google Play Music app.
Sidebar: cool. You could use a sidebar on the other side for notifications later.
Up button: it's usually used for going 'up' to the previous Activity, you're right, but in the past it's also been used for going back to the previous interactive element. Up to you whether you use it.
Silhouette: throw the icon in the Launcher Icon generator and it should spit out a silhouette'd icon ready for use in the app.