There are no real options. You either use a Google enabled phone with all it entails or you use AOSP with no Google Play and less and less functionality with every new version.
Not yet. From what I read it could take up to a month to roll out globally.
I'm from Peru, South America and was able to login, register and install the App without problems
Run Windows Update again AFTER you install those 5 updates and it will appear. Finally after installing and installing the 800MB update run WU again and a new update (2MB) will appear
Do try to remember that Office 365 University is available to students for a single payment of $80 valid for 4 years and that many educational institutions offer the Office 365 Education solution...