You are incorrect about the arranger of the organ part. It appears to be Bruckner's own arrangement. Goller just updated Bruckner's score to be playable on more contemporary organs. Carolus 01:39, 27 July 2010 (UTC) (IMSLP Copyright Admin)
I'm happy to be corrected but I am not aware of any published arrangement in Bruckner's lifetime with an organ accompaniment. I understand the preface to say that the main obstacle to the work's performance is that it is set for wind, and to make it more performable he has arranged the accompaniment for organ "die Begleitung fuer Orgel zu uebertragen".