While it might be Kurashima, 60% chance is probably too high, considering how he was mentioned in the chat. Personally I would not be surprised if Takai is jealous and the real culprit. It is going to be interesting to see how this will unfold.
And the girl count is just increasing. It is like the author is out of plot ideas and just decided to compensate by adding more girls. I would want a bit more of a real plot, and a bit of gaming and scheming between the characters.