It's unclear to me that a Druid or Cleric knows their spells---that language is not used in their description. Wizards know spells, as do every spontaneous caster.

Perhaps a better way to exploit this is via Wizard 7/Archivist 1/Hathran 3 since Wizards and Archivists surely know their spells.

Do note that Universal Spirit Magic (at 3rd level) applies everywhere.