From what I remember, we were pretty sure it was Naked Yumemi as Okina kept spwaning after one was killed. This was late at night when there were single digit people in the instance so it was unlikely to have been triggered by someone else. I'm not sure we ruled out normal shelled Yumemi as a trigger. You can go back through the hunt forum if you like? http://forum.square-enix.com/ffxiv/threads/185390-Let-s-talk-about-Hunts-a-detailed-rundown-of-their-assumed-mechanics/page246 People might have added more info about Okina that I missed. So, pretty sure Naked Yumemi is a trigger. Haven't ruled out normal Yumemi also as a trigger. Hope this helps :)
