User blog comment:Project Predacon/Volume 2: Post Credits Scene Analysis/@comment-13499046-20141031001109

While I was (and really still am) in the "she's Yang's Mother" camp, the idea that she's not is actualy quite interesting. While it seems heavily implied that she is her mother, it could easily be misdirection, particularly if Yang merely believes she's found her mother when in fact it is actually an entity serving it's own ends (be it a nega-Yang, Yang-from-the-Future or whatever) which could be an interesting story development.

I'm curious about your incest comment though, why can't Qrow and Raven both be Branwen's? Taiyang could be Yangs father, Raven her mother and Qrow her maternal uncle.