They already answered a little on the Tattoo–TV Guide Lightening Round 3.
Will we find out about Emma’s tattoo?
Adam Horowitz: I would say probably not.
Kitsis: It’s the same flower that’s on her father’s crest, but how she got it and why she chose it is probably not something we’ll get to this year.
I don’t think the characters in FTL generally have last names. Snow White is her name, like Mary Margret is her name in SB, but of course there she also has the last name of Blanchard. Rumpelstilksin didn’t have a last name. It’s quoted on his war letter as one name, not like his first name is Rump and his last name is Skin. Now I’ve just recalled RC and the Full Monty, and can’t stop giggling.
“If I had a world of my own, everything would be nonsense. Nothing would be what it is, because everything would be what it isn't. And contrary wise, what is, it wouldn't be. And what it wouldn't be, it would. You see?” -- Lewis Carroll, Alice's Adventures in Wonderland & Through the Looking-Glass