I don't have your phone, but we're both running Android of course. In my experience with a bluetooth earpiece that's typically meant for calls, it'll only pair for phone audio, and if you're on a call and using navigation per say, the navigation audio will temporarily be routed to your earpiece, as will notification noises. If you go into bluetooth settings while your earpiece is connected, you should see that it says "Connected to phone audio". If you purchase a bluetooth device meant more for media, it ought to work with that I would suspect. For example, I'm also paired with my laptop, and I can specifically turn on a media connection to play music from my phone through my computer, and control it from my computer. When I have that turned on, it says "Connected to media audio." under my laptop's name, again in bluetooth settings. I can also turn on both features, and it'll say "Connected to phone and media audio."
From the above, I would also expect that if you get a bluetooth device meant to pair to play media, it will be able to play media and also handle phone calls. It is possible for me to use my laptop as a "handset" (using speakers or headphones and a microphone) with my phone.
Hope that helps.