Does Mojave use something in addition to fstab to automount drives?

I'm trying to mount a second internal drive at /Users, but the drive will not mount until after login.

Previously, I believe in Sierra, I had the same setup. I mounted the encrypted Users drive to /Users on an encrypted Startup SSD with fstab

UUID=[[user drive uuid]] /Users hfs rw,nobrowse

I also copied the password key from the local keychain to the system keychain.

In this way, the drive would be automatically unlocked and mounted prior to login, and could hold the Users folder no problem.

Now in Mojave with the same setup, the drive will automount only after login. I've tried using an unencrypted Startup drive, putting "mount -a" in a LaunchDemon, and a million other things. My current work around is to auto login to the guest account, which mounts the encrypted Users drive. Then log out and log in to my normal account and all is fine.

Does Mojave incorporate some new system separate from fstab? Is there a way to trigger auto mounting internal drives earlier in the boot process, or maybe from clover?

For completeness sake, I have an old Gigabyte GA-Z170MX-Gaming 5, i7-6700k. Unibeast to make a USB and an old clover config I've been tweaking for years. Startup disk is an APFS SSD with 10.14.3, Users disk is an internal JHFS+ Fusion drive.