(Time to be the cynic, again).
You guys realize what Annabelle asked, right?
She just asked to be friends with a head of a founding family. Talk about catapulting oneself to the higher layers of that society. She probably went a step bellow Alison in influence by winning that competition.
Ok, even I don't completely believe myself here, she is just too sweet. But it is a possible interpretation. My personal bet is on a Hannah or similar type situation - I don't think she has sinister motives, but I'm sure it's not just "lonely girl seeks a friend". Unless she stays completely as a comic relief.