I can now clarify with respect to Windows Phone 8, as I've used it (Lumia 920 Update 3 developer preview on AT&T) with Google Glass XE11.
Here's how things work as they are now:
- Glass can pair over Bluetooth to Windows Phone. Glass shows up as a voice headset. I didn't bother to test making & receive calls... I think it's safe to assume this works. This appears to be the maximum Glass can pull off with "any Bluetooth phone" with nothing but Bluetooth. Caveat emptor.
- Glass works quite well with Windows Phone Wi-Fi Internet Sharing. You have to toggle Internet Sharing on/off manually* on the phone, which is not ideal. But once toggled on, Glass has internet connectivity wherever you go, instead of only when you're at (preconfigured) Wi-Fi APs. I haven't had Internet Sharing toggle off automatically yet in this configuration, which is good (it doesn't disconnect) and bad (it'll burns my phone battery down a good 15% an hour with almost no use of the phone or Glass until I remember to turn it off.) Thank goodness for Qi charging of Lumias.
- Glass is not able to do directions & SMS messaging in the above configuration. These scenarios (currently) require a Bluetooth-paired Android device running the MyGlass app... you need an Android device for no other reason, not even for setup! But if you want to try directions, and you have a Wi-Fi Android tablet (like Nexus 7), you Bluetooth-pair the tablet with Glass, and set the tablet up to use Internet Sharing too. Then you get directions whenever the tablet's "in your bag", and when it's not, oh well. SMS messaging is enabled in this configuration too, BUT it's buggy and may not work at all. Glass did let me send texts, but only once told me a text was not delivered... but no texts were delivered. Hmm!
The above works well enough for "explorer"/developer scenarios for certain. I can't say the XE units are for much beyond those scenarios anyway, so I'm not complaining at all. Hopefully this helps.
(*Has Microsoft shared the protocol used to turn Internet Sharing on automatically through Bluetooth in Windows 8.1? If so, I'd think Android/Glass could implement it.)