Once Upon A Fan

Was Swan the name given to her by her adoptive/foster parents or where did she get the last name of Swan?

There is a German fairy tale by Brother's Grimm called The Six Swans; "Six brothers from a King's first marriage have been turned into swans by their hateful stepmother (a beautiful but evil daughter of a witch). The brothers can only take their human forms for fifteen minutes every evening. In order to free them, their sister must make six shirts out of starwort for her brothers, and neither speak nor laugh for six years. The King of another country finds her doing this, is taken by her beauty and marries her. When the Queen has given birth to their first child, the King's own wicked mother takes away the child and accuses the Queen, and again with the second and the third."

When Blue Fairy gave Baelfyre the magic bean which sent him to a place without magic she told him that there used to be more beans but that was the last one.

Also how many times was the EQ married? Only once or more than once? Or were there other times since there are plenty of stories about evil queens and wicked step mothers?  It would be kind of interesting to see a battle between all of the Evil Queens or Wicked Step-mothers and the fairytale families they attempted to destroy. Of course I'd like to see a happy ending for come true for Regina too cause she wasn't always evil. 

My Theory: What if she gave a magic bean to one or more of the six brothers to use while they were in human form? Blue Fairy probably told them that she could not stop the curse on them or change it in anyway but with the use of the magic bean, they would be able to live in human form until a way to end the curse could be found and they could safely return...perhaps they were given a way to return. They wouldn't have to live in Storybrooke, just like Emma, August & Bael didn't have to live in Storybrooke. So perhaps Emma lived with one of them as a baby until she was 3 years old and this is how Emma came to be given the surname of Swan.  Now in the story of the Six Swans it doesn't actually say what the surname of the family actually is...but what if it was Swan & that is how the EQ stepmother decided to turn the 6 brothers into actual Swans?