A nice solution is to use Public Session settings in Chrome (https://support.google.com/chrome/a/answer/3017014?hl=en). No need to have Google accounts. Instead push out a Single Sign On solution such as Unify which the user can then authenticate into o365 (and other Apps). This solution gives you the ability to manage the device (you will need a license on each Chromebook) through Chrome Management, although of course it won't give you user settings. Device management in Chrome still gives you a bunch of controls (https://support.google.com/chrome/a/answer/1289314?hl=en).
