So I think Kitsunehara Konkon is the nerdfriend who told them about the stream.
On the surface, that idea should be absurd - he wasn't there, so he shouldn't know what happened.
Except, he did - how else was he able to tell that the stream was about Airi?
After telling Airi about the stream, he drops several convenient hints pointing to Kendoboi(Kashiwagi Tsuyoshi) - which I assume was the goal of this stunt, to sell out his friend for reasons unknown. His connection to Kendoboi would also provide him with all the intel he needed to pull it off - the event, the furrydom, and even the injury, which he leverages after the meeting with Airi fails to create results.