I managed to complete the election, but as I was saying, that was not a problem. I couldn't get the event to trigger in the first place.There's a walkthrough in the OP for a step by step.
But to install the spy cam in the girls shower, you need to go to school in the \early\ morning.
My mistake was not talking to Lauren in HQ, because I was sure it will repeat the lightbulb poster scene. Once I tried everything, gave up and talked to her in HQ, I finally pushed the events further and had no problems after that.