Working for the BATD, I have Sharon as head of security. She is also the liasion between BATD and local law enforcement, so if Lily does end up working for BATD, she would definitely get to meet her. Since she's pre-established, she could have been a part of the team that answered Jess' call for help with Allison last night, if you want!
You are welcome to plots with any of my others, as well! Since I am assuming that Lily will know Alicia and Katie, she'll probably have met Rory through them as well as probably Rose and Caroline. And you know Rose's BFF is the head of all the BATD so there's that too!