Just an update, I uninstalled KB4023057 and rebooted the parent image then downloaded wushowhide to try and hide KB4023057 from future updates but the tool wouldn't list KB4023057 as available. I'll leave the master image up and see if a.) the Windows Update service gets re-enabled and if it does, b.) I'll run wushowhide periodically to see if KB4023057 appears in the list for me to hide.
Fingers crossed.