For the "Rigamarole" cast:
Riley would look like he didn't want to be there at all. He would want to avoid his friends smacking him playfully or pushing on him and seem annoyed by everything.
Leia would be in the middle of gossip about who likes who, and who should ask who out, but if it ever got malicious, she would turn mom mode and make everyone behave themselves. everyone would immediately get quiet and obey her.
Ryan would somehow be at a girls slumber party, and they would be telling him all their gossip, not think it's weird, and simply explain without qualms anything he didn't understand about girl talk