I think there should be plausible denial of the group being linked to BSIC, since we want to recruit normal people into our ranks so that we appear "moderately normal" to the unsuspecting public. We need someone with an ostensibly normal background to be a figurehead. Jen, you think uncool sister would work?
It will work, she's the Sisteren in Bretheren & Sisteren in Chaos.
Remember the "Shadowy secret member" kept safely secret except from we who know stuff.
And she is much more normal than either of us.