Dual Booting BSD with Linux

I have not yet figured out how to do this.
BSD needs ZFS partitions.

Latest Debian should be able to recognises ZFS partition.

It all depends if the GRUB boot loader can configure it.

I will Mount BSD first leaving behind space for Linux to install later.

Problem with BSD is it takes over the whole of the hard disk and one cannot resize it.

ESP partition is where GRUB is recorded and somewhat large ESP partition may do the trick.