Stop me if you've already posted this, but I couldn't find anyone talking about it already, which may have just been how I was trying to search. As always, standing on the shoulders of giants, in this case, Per Olofsson's CreateUserPkg. Been using it to deploy one of our hidden service accounts during build with AutoDMG. With ≤10.11 it's always worked to hide our service account if the User ID is sub-500.
Starting with testing out an image for 10.12, the User is not hidden. It does create the home directory where we want it (in this case /var/hiddenuser), but it's presented at the login screen, even after rebooting, and it's listed as a user under System Preferences > Users & Groups. Is anyone else encountering this? I could go back and script out JAMF creating/hiding the user, but the CreateUserPkg was a clean, easy way to do it during an image build.
I can probably, easily I would guess, push something along the lines of
sudo dscl . create /var/hiddenuser IsHidden 1
but having to run that after the fact seems less than ideal to me.