Airi probably realized Ise, Andou, and Taira are doing what Kawasaki (the smug glasses guy in the prequel) was trying to do right off the bat of the previous game - forming an alliance to guarantee his own survival. I'm not sure exactly what Airi is doing, but she might be trying to use the fortune teller's authority to toss suspicion toward Taira, whether Inoue decides to claim the fortune teller or the real one steps forward. If Inoue goes uncontested, the bodyguard will probably be on her for the night. Other than that, the best option then is to study who has a heightened interest in the conversation, which could lead to either the fortune teller or the bodyguard subconsciously revealing themselves. It's even better this way since their roles aren't revealed upon death, so killing any special role early in won't be so noticed.