Nope, I have tried both quarterstaff, one handed weapon and two one handed weapons. On having done more play time with Hiravius it seems to work but only sometimes. I'm not sure if its checking for a certain length of combat or what but he seems to spiritshift without me commanding it actively about 1/4 combats total.
On attempting to do the alternative entry options to Raedric's Hold (Sewer and Vines) the game does not open what I assume is the standard interaction dialogue screen but instead pastes a description in the chat log with no option to respond to it.
Beyond this doing this seems to permanently disable saving until you reload and similarly stops you from interacting with any other dialogue box spawning object. Reloading the save and going back to it, loading a save in the zone and resting all do not fix the issue making them permanently uninteractable in my save.