Assuming you have the following deployed to your users:
- OneDrive for Business sync client
- Microsoft Sign-In Assistant
- Office 2013 / Office 365 ProPlus
(I haven’t explicitly validated this, but it is what I have installed on my test PC)
…then configuring Office to use a SharePoint Online library for Shared document templates is pretty easy.
Using a registry entry, you can simply set the following key to the WebDAV URL of the Document Library.
Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common\General] "SharedTemplates"="\\\\[email protected]\\DavWWWRoot\\path\\to\\templates\\"
I will follow up this post at some point with the ADMX route.