Leon was there, obviously. He flew solo, but definitely mingled, especially once he got a couple of drinks in him. He was wearing something like this (he cleans up nice).
Laurence came dressed in his dress uniform for the Aerial Corps (something like this, though he has bars on his shoulders, not epaulettes, and no hat), probably with Lan Xichen. He likes to dance, and probably would've asked Carol for at least one!
Peter</a> was also there, looking dapper in a suit. I imagine he spent most of the night with Kate and Kamala, but he would've asked Carol for a dance too!