I’m not sure if this is helpful to you or not, because it’s not what you asked. I just don’t mount them on boot though.

I have a script that requires a unique password that decrypts everything. If that hasn’t been run, then the server starts emailing me every 15 minutes until I do.

The server is not setup to reboot unless I manually tell it to or there is a power outage, so logging in to run the script has never really been an issue. At most, I’ve had to SSH in from my phone maybe a handful of times.