I used to have an issue with installing Office 365 offline. The installation failed, when mentioning a branch in the xml file.
You can find a threat from TechNet on this link:
https://social.technet.microsoft.com/Forums/en-US/b8ec9bb8-6122-4f85-ac9b-ebff3aa301d6/how-to-install-office-3652016-on-clients-without-internet-connection?forum=Office2016ITPro
The solution was, not to mention the branch in your xml file.
Last week, Microsoft updated their Office Deployment Tool. Now, the offline installation works fine, even when mentioning the branch in your xml file.
https://www.microsoft.com/en-us/download/details.aspx?id=49117