You said "Additional Class Notebook features: The full slate of Class Notebook features available in the add-on for OneNote 2016 will be available in OneNote for Windows 10 this summer. Best of all, you no longer need to install a separate add-in—it's all built-in!"
I use OneNote Class Notebook with my Office 365 for Education accounts (I have two). I also use OneNote with my Office 365 Home, and two Office 365 Enterprise E3 accounts. The Class Notebook (add-in) tab would show up in all of my notebooks no matter how I am signed into the notebook. Are you saying class notebooks will be available in all Office 365 subscriptions? Usually when I am recording demos, I turn off the Class Notebook tab via Options) As you know, the options in the Windows app is very limited compared OneNote Desktop. How will this be handled?