I got nothing on your volume issue.
Pretty sure you will not have the separation of notifcations. If It is there, I missed it. Have you looked at Profiles in Cyanogenmod? Those do exactly what you want for several default profiles, including default/night/work/silent, and the ability to create whatever more you want. Profiles are pretty sweet, doing more than just independent volume control too, including disabling data, wifi/gps/lotsofstuff on/off. You can even go deeper for individual app stuff.
I will shut up if rooting is out of the question. I am talking about flashing a ROM to solve a problem, so.
There is also Tasker(app, root), which you can essentially script based on time of day, toggles you make (etc) and independently change volumes. Tasker is more difficult to get started with, but is not limited to just volume control either. Its a lot like a graphical script creator. Profiles is easier for just volume control, but Tasker is useful for quite a few tweaks that are very specific to you
(start Pandora when detecting connect to car BT, Also enable screen rotation, set screen timeout to 59m, and so on. You can get Super Geeky in addition to the basic stuff if you wanted to.
You can cover a lot of ground with both Profiles and Tasker
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Throw in NFC tags ftw.