I like the theory that they are related in some way, but I don’t know if this is how. If u remember the real story of Rumple it says that the millers daughter aphid to spin hay into gold, we know that Cora is the millers daughter. We do not know how old Snows mother was compared to anybody, but I would guess between Cora and Regina’s age.
My crazy theory is that Cora spun hay into gold for King George and fell in love with him, but she and Snow’s mother were friends at the time. They messed around with magic because they wanted to stop the deal made with Rumple and Cora became barren. The only way to stop this curse was to go to Rumple. He would help her if she left King George, so she pretended to die and went away with Rumple because she needed to due so. Because of the original deal Cora had with Rumple, Cora had to marry and have a child, She married Henry senior and with Snows mothers help, learned how to use magic so that when Regina was born she would be able to stop him. She and Snow’s mother tried to stop Rumple but he would only yield to them at one cost, if Snows mother promised to marry a king. Rumple planned this out because she knew that Snow would have a true love and help bring on the curse. After living with Leopold, Snow’s mom got everything, including a daughter even as a child proclaimed the fairest of them all, she wanted but Cora was left with barley anything. To get even with the person she was friends with, she killed her. After her death Cora learned that the king knew nothing of her, so she planned that her daughter, who was a young girl at the time, would take place for Snow’s mom, being that it was because of the child that Snows mom got the honor if being a queen. She waited years until her daughter was old enough to take her friends place and when the king and his daughter were traveling through the kingdom and bam! She spooked the horse of Snow, the daughter of her friend, and Regina being a horse lover was able to clime on her horse and rescue Snow. And we know what happened from there…. Mostly
Keeper of Swanfire's dream catcher, the Blue Fairy Plot Device, the contact name "Her", the lanyards, the trigger, the Netherworld room and necklace, Charming's quote on Thanksgiving, and PP's pic of Henry