From apples perspective you can purchase a Mac server with the iOS apps caching server. But it relies on the fact you have a static external IP for your school.
Has the server been windows updated recently. I had similar on a 2008 R2. After a reboot the authentication worked. If you accessed the web page on the server it worked but not on a PC.
Can't you just approve this update in wsus. Then in MDT it should pick it up in a build and capture. Worst cast wusa.exe as an application before windows updates. Seems easier. Offline servicing has always been a bit of a dark art. Particularly because the install.wim from a win 7 sp1 iso has an out of date wua. Most people put office in their image which means that you have to do office updates in the running OS anyway.
The ink support will be good for touchscreens/smartboards. I prefer the start menu as I've loathed having to click all programs, particularly if frequently used programs are disabled on the start menu.
http://www.zdnet.com/article/microsoft-onedrive-for-business-to-get-sharepoint-document-sync-by-year-end-2016/
May just be for the sync client. Which still isn't up to scratch. *cough* placeholders *cough*.