For those of you continuing to struggle with this issue, I wanted to provide you with the specific fix that worked for me, which is a variation on the theme. I did not end up having to reinstall Windows, which would have been a nightmare. Hopefully, Apple addresses this issue soon!
I was finally able to boot into my system after a god-awful number of tries. For some reason, it only occasionally works, with seemingly no rhyme nor reason. I tried variations of holding "option" at boot and selecting the boot camp partition, and booting into safe mode on the rare occasion that I was presented with recovery options. It also seemed like variations of having an external monitor and power hooked up seemed to help it boot – I never did get it to boot into Windows without being “docked.” Anyhow, all speculation… but if you can achieve a boot or safe mode of some kind:
In Windows Device Manager, I attempted to disable the Bluetooth adapter as mentioned in other threads, but it did not do anything – the same problem persisted. After trying many other solutions/restores/etc., I looked at the “devices by connection” view of device manager and noticed that Bluetooth was a child of “Broadcom Serial Bus Driver over UART Bus Enumerator.” I tried disabling that parent device (it is under “System devices”), and lo and behold, everything is rock solid again with multiple reboots.
While I have to live without Bluetooth connectivity, I think this is better than reinstalling the whole setup… hopefully we just have to live with that limitation until Apple issues a real fix and then we can re-enable Bluetooth.