We've added the installer to the SCCM machine build task sequence, and it hangs while installing. Two hours later the task sequence times out, tosses an error, and dies.
I discovered that the Office Installer was running this command:
"C:\WINDOWS\system32\wusa.exe" "hotfixes\Windows6.1-KB2999226-x64.msu"... and that was causing the Windows update agent to peg a CPU core and do something it never finishes.
The fix for this is easy. Before running the Office 2016 installer, stop the Windows Update service. Don't disable it, just stop it.
The command to do this is
"sc stop wuauserv"
The service will automatically restarts on the next reboot, and after the installation I found no other issues with the system. You can uninstall, reinstall, modify, and update Office normally.