It's not really a multicasting device so what ever you are doing is right there in your face all the time. There is a bit of a notification bar when you have certain music apps going that will play in the background until you choose a new app.
Android TV (and Google TV) Home screen does support notifications with a notification card at the topmost of all the card views to lists all the notifications used by the apps running in the background (for example, Spotify does use this feature)... Besides that, it does have a "bar" of small icons on the top right corner next to the current clock that functions as a status bar with quick menu options. If there is any notification, a small icon with a notification count overlay may appear and the count will decrease if you have removed any notification from the notification card.
Haven’t used my mibox with atv on it for a while since getting the chromecast with gtv but there is a notification “panel” on gtv. No clue about music controls on homescreen/dash for either but that’s because I generally just cast music from my phone so I control it from there anyways