When I began seeing more of Cora’s interactions and her comments in Queen of Hearts I kept thinking of the film Serial Mom. Cora does seem a bit happy to rip hearts out of people who do not fit the means to her ends, she has no problem trying to use what is basically domestic abuse to get Regina to conform and accept her instruction (more like commands).
Prior to obtaining magic I suspect that she was already displaying some of the characteristics we see today to a lesser degree and with the limitations of being without magic.
I know it is a stretch but I researched her name found that it was a latinized version of the Greek name Kore meaning maiden. Thinking about maiden definitely reminds of the story of the Miller’s Daughter. There is a variant called The Three Spinners where in this version the daughter where she spreads false claims about her spinning abilities. I wonder if an alternative look would be that she overestimates her abilities and becomes extremely arrogant.
I would then wonder if maybe she has a skill of charming her way out of things with words and actions. As for Rumpelstiltskin he may have asked for a first born as a means of trying to replace the space that Bae once resided. So either Cora bested him or Rumple, being prophetic, sees far into the future. He sees the darkness to come but sees the magic of true love (Snow and Charming seem to be the stronger ones–or at least continues to be. Not sure if true love can die if not nourished.) and Regina’s curse which would put him that much closer to Bae.
I sort of think that his teaching Cora and Regina was definitely part of the plan. As was nurturing the parts of their personality to fit his plan. I also do think that he realizes that Cora suffers from hubris and like the Greek origin counterpart it will be her downfall (she is in her own tragedy–a FTL tragedy). In the end not only does he best Cora in the end, punish her for her hubris, pushes Regina (Cora and Rumple) into using the dark curse and it allows Rumple to come to world that has Bae (perhaps curse has a honing device to set Storybrooke in the time and place–i.e. general area close to Bae)