I just upgraded to macOS 10.14.3 from High Sierra. My Mac has multiple user accounts and so far (i.e. macOS 10.12) I could always manage which users were allowed to unlock the encrypted Filevault2 volume pre-boot (image downloaded from this website):
However, in Mojave I cannot find the option to do so anymore.
(How) Can I enable and disable individual accounts for FV2 unlocking in Mojave?
Update: After disabling one user using the command line, the dialogue is now available in the System Preferences.