Ah man been there, done that!
I now specifically use the dated archive mirrors for arch mirrorlist as well as the zfs-linux AUR package over the DKMS. Been a lot less of a headache dealing with it that way. I just bump the date up to as far forward as the two packages were aligned and off ya go.
I do wish the licensing would get sorted out because I love ZFS but dealing with always having to juggle that dependency is annoying.
Also mkinitcpio should be much more aggressive on failing on errors.