Bluetooth security: does GOS check for encrypted connections?

I know that BT has many vulnerabilities. Does GOS offer any hardening against BT? In particular:

If I connected Bluetooth keyboard, can I verify from GOS that the keyboard is using encrypted connection?
If a malicious device (think of Hak5 Duck) is paired with GOS, what info can it gain and what attacks are possible to it?

How well are Bluetooth devices isolated from the system. i.e: what can they access? Can a headset for example connect to the internet?