Yes, headless. VNC, behind a locked door. It handles the FM audio processing for the community radio station I volunteer for, kpov.org. If at midnight there is a power outage long enough for the UPS powering it to run out of juice, we don't need to have someone have to get out of bed and connect remotely to get it up and running again. Power on, run the script that gets JACK and the clients up going unattended. I'm not running into any issues with the @reboot cronjob.
I see from your code that you first get jackd running then load jack-plumbing. I suppose that my various jack clients can be loaded after that and jack-plumbing will do what needs to be done to get them properly wired up.
Thanks for your assistance!