As for GoldenHearts, I don’t know. Belle’s purpose there is to keep Rumple from making the selfish and easy choice: letting Peter have the boy. The Cora Rumple knew, the one who thought power was the important thing someone could posses and who ripped out her own heart, would probably let Henry die and would encourage Rumple to let it happen so that he is not “undone.” Belle is Rumple’s moral center but Cora represents the Dark One’s equal.
Vilya suggested that Regina, not Rumple, could have a vision of Cora. Regina seeing her mother would be very interesting since Cora was very abusive right up until the end when she got her heart back. On the one hand, Cora could represent Regina’s darker side which prompts her to want power and magic over love, yet Cora’s last words to her daughter “this would have been enough” could help Regina realize that loving Henry is all she needs. Regina doesn’t need power or magic to be happy. (Though as RG pointed out, we’ve yet to have confirmation of Barbara Hershey being on set).
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy