Edit: Oh yes, SNSD has been confirmed for the OST.
Word has it that SNSD (well just one of the girls, not sure who will take it though) has been offered a role in Iris 2. Whether major or minor, I’ve been hearing a lot of different things. Some say Yoona turned down the role due to promotions and other stuff. Anyway, SM has yet to release a statement and they might even turn it down but just thought i’d keep you all in the loop!