I checked proposed and the amd64 versions finally built. I installed v2.13.1-0ubuntu0.20.04.1, removed my temporary fix, rebooted, and am pleased to report that ovsdb-server is now waiting for ZFS to mount. Manual inspection using "systemctl list-dependencies ovsdb-server.service --after" shows dependencies on the relevant ZFS mounts as well.
I checked proposed and the amd64 versions finally built. I installed v2.13.1- 0ubuntu0. 20.04.1, removed my temporary fix, rebooted, and am pleased to report that ovsdb-server is now waiting for ZFS to mount. Manual inspection using "systemctl list-dependencies ovsdb-server. service --after" shows dependencies on the relevant ZFS mounts as well.