Since this seems relevant to my particular problem and is the only thread I can find about this specific issue with bluetooth missing in action after installing a 64-bit version of Windows 10 (the 1607 July 2016 release) on a MacBook 12-inch 2016, I was able to solve my particular issue with the following fix. From Windows services, locate the two Bluetooth related services and ensure they are configured to start "Automatically" and start them if they are not started. Mine were set for Manual and were not running.
Next, go to Device Manager in Windows and expand the "System devices" branch (if it's not already expanded). In my case I had an alert symbol on my "Broadcom Serial Bus Driver over UART Bus Enumerator" device. Right-click and select disable. Then, right-click and re-enable it. My bluetooth functionality magically appears shortly after doing this. The bluetooth icon appears in the system tray, and is now available in Windows settings.
I still have to do this from time-to-time with my MacBook 12-inch 2016 after rebooting Windows. On the macOS Sierra side, all works perfectly.
To be complete, I had re-installed the Bootcamp drivers several times from a USB thumb drive, even the specific installs for the Broadcom related bluetooth drivers,prior to settling on this fix described above.