We did the upgrade via Self Service as well. Created a Policy that
cached the Mojave installer to any systems with an earlier version of
OSX. Then created a Reimage Mac OS Policy and set it for Self Service
only and leave it disabled until I want to ...
My environment has Enterprise Connect and Jamf. My understanding when we
set up Enterprise Connect was that once you logged into Enterprise
Connect it would change the user account password, but that doesn't seem
to be the case.