I've created a script that does all of the above... if you want to use it, you'll have to edit it to reflect your drive UUIDs, PARTUUIDs and device paths.
It's here. I've set it up as a keyboard shortcut in Zorin menu > Settings > Keyboard Shortcuts.
[EDIT]
I've since added another mirror drive to the rpool... the script quickly gets complicated and lengthy (and takes a long time to run) with multiple drives. I've got a feature request in with OpenZFS to automatically erase the zpool initialize progress data once it's finished initializing, so it can be run multiple times, as that has several advantages... it reduces the size of VMs, it erases potentially sensitive data sitting on now-unused sectors, and it makes your compressed backup .IMG files a lot smaller.
With all the stuff I strip out on a new install, and with zeroing the drives via zpool initialize, the backup .img file now compresses to a mere 2.2 GB for the 1 TB internal drive.