The joke is that Hashimoto Kanna played the live-action Teruhashi Kokomi.
I'm not sure if Yoshioka Riho has any Saiki-related roles.

Huh? Did Chiyo knows Kokomi have feeling for Saiki?

Dang y'all chose some very average majors. I guess no one in the group would suit being like a rocket scientist or something though. Especially Kaido though? Communications? Really? Kaido Shun, chuuni nervous boy?

damn, that ending was pretty serious