From what I can get from the Twitter post, it should be a Rokka and Ako 4* and the others would be Mashiro, Rui and Chu2.

As for the type, I think it'll be powerful. I know Ako had a lot recently, but Rokka's only powerful card is her initial 2*. If not powerful it would probably be happy and Rokka had one last time, but it's bandori type so we never know.