I think "Bing Maps powered by Here" will replace "Here" on Windows platforms. MS already start to integrate their own Maps app with Cortana, and integrate transit info into their Windows app, and...
The so called first phone business is Nokia's feature phone business, so it is not that "important" to Windows phone. Basically, X is dead and Asha line will be gradually phase out.
Plan C is suicide. Although Android is open, only Google knows what's next for it. So if MS replace Wp with AOSP, its mobile future will be in the hand of Google.
Spin off Xbox and Bing? Without an entertainment offering (games, musics, videos...) and an information/cloud service, how could MS compete in the consumer space?
how about weight? Will it be lighter?