<3 Why not a mix of all three: Goshi's arrogance, Botan's energy and closeness to Yoko, and suspicion that she may be someone from Spirit World given how quickly she entered the school after these suicides occurred along with her distinct spiritual energy? It's just using the Yoko portion to heighten his abilities, since while in the Shuichi base form he's pretty gimped in all things. The lackey could be distracting Kurama, and then tip Kurama off either intentionally or not that Botan is in danger? Botan being snappy and unpleasant is a warning sign since that's clearly not her, but given the stress of the case he may not figure it's much more than concern that they're not making any immediate progress? Could Yoko ever separate from Shuichi and actually warn him of things happening elsewhere?