Worth mentioning aside Alpine (and other small Linuxes) supporting ZFS just fine, we also have ZFSBootMenu, which is frankly a hell of a lot better than the boot environment experience in FreeBSD.

https://docs.zfsbootmenu.org

From within the bootloader's interactive (fzf-based) menu, you can:

    * Select boot environment (and change the default boot environment)
    * Select specific kernels within each boot environment (and change the default kernel)  
    * Edit kernel command line temporarily  
    * Roll back boot environments to a previous snapshot  
    * Rewind to a pool checkpoint  
    * Create, destroy, promote and orphan boot environments  
    * Diff boot environments to some previous snapshot to see all file changes  
    * View pool health / status  
    * Jump into a chroot of a boot environment  
    * Get a recovery shell with a full suite of tools available including zfs and zpool, in addition to many helper scripts for managing your pool/datasets and getting things back into a working state before either relaunching the boot menu, or just directly booting into the selected dataset/kernel/initrd pair.

It also supports 100% of ZFS features that the host system supports, since it uses the ZFS kmod. That includes native encryption.