@juanelric
None, so far. Kako mostly talks only to Bocchi, plus one conversation with Nako.
I merely thought of Mina (again, jokingly) because of the contrasts: one is laid-back and friendly, while the other is serious and actively un-friendly. You know, it's opposites like those that I really, really like.
Before I realized, I had imagined a full scenario about Mina falling for Kako (born from getting a tsundere reaction from her), and asking Bocchi for help to get closer to her, since she knows the most about Kako in the class.