Kate at the bar
Firstly, was she old enough to serve alcohol? Maybe it's a small town and no one cares.
More importantly, why weren't the gremlins trying to kill her right off?
She seemed to be over 18, and I believe the minimum drinking age wasn't 21 at the time.
As for the Gremlins not killing her right off, I assume most of them simply wanted to chill while they made someone serve them. Also, they probably spared her because she was good looking (things might've been different with another bartender).