North, ZRS: Hey! So FWIW, here's an idea on how all our character's might know each other:
Elena and Jack's father's were close geographically if not socially - Elena's dad was a wealthy noble, Jack's an impoverished one. They both backed the expedition to the New World that Silence was on - when that expedition failed it bankrupted Jack's dad, but was only a minor inconvenience to Elena's family. Silence approached Elena's father for help after her return to England as an orphan, but he wouldn't even meet with her. Elena however, being the person she is, decided to partner up with Silence to seek their fortunes together. At about this time Jack returned from the Continent to discover his family had sunk even lower financially. Since Jack was back "in the Shire" so to speak, Elena approached him and asked if he'd like to team up with her and Silence - remembering the unconventional, free spirited girl who used to prowl the woods with her bow, Jack said sure.
Not exactly Game of Thrones, but I think something along these lines beats the usual "you all bump into each other at a tavern one night."