Apologies for not replying sooner, your questions may be moot at this point... but here are some pointers and suggestions.
The site here has a wiki page dedicated to booting from a ZFS filesystem:
https://openzfsonosx.org/wiki/ZFS_on_BootAs for the lesser goal of simply having a user home directory on ZFS, this is relatively simple. There are some tradeoffs for security and convenience, as usual. Assuming for the moment that you have an APFS partition for booting, I would recommend that you always maintain a separate admin user with a home directory on the APFS boot volume. Then you are always guaranteed to be able to boot up and log into that user to fix things, if necessary.
I maintain two different logins on my machine; one is the admin user with home directory on APFS, and one is the everyday user with home directory on ZFS. The way that I set that up is to initially create the everyday user with a home directory on APFS disk; I don't migrate any data to that user yet, but I do log into it and sign into my iCloud account. Then I log out of the account and switch back to the admin user. With the admin user I set up ZFS, and create dataset on the pool for my new everyday account. To allow for expansion, I create a directory structure of TANK/HOME/Users/everyday and set up permissions to match /Users/everyday. Then I use the terminal command "ditto" to copy the entire folder /Users/everyday to /Volumes/TANK/HOME/Users/everyday (meaning I copy the directory structure and files that exist under APFS over to the new directory structure under ZFS). Finally, I go into System Preferences > Accounts, authenticate, right click on the everyday user, and select "Advanced options." This will take one to the screen that allows you to specify an alternate location for the everyday user's home folder: /Volumes/TANK/HOME/Users/everyday . Reboot for the changes to take effect.
Can you boot and log into your everyday account on the ZFS filesystem? Theoretically, yes... but I always log into my admin account first after a booting up the machine, just to be sure. That way I can issue a "sudo zpool import -a" if necessary. What I've noticed is that if I have FileVault turned on for the boot disk (MacBook Air) the auto-import script (which is set up by the installation of ZFS) seems to always import my ZFS volume just fine. On my Mac Pro 5,1 running Mojave there is no support for FileVault on the boot volume (since there is no graphics card support during boot), and the ZFS pools never mount. So on the Mac Pro I always log into the admin user, unlock disks if necessary, and manually zpool import.
Hope this helps.
Kurt