I was initially really upset that Alice wasn’t going to be Grace’s mother. I think if they could have gotten unrestricted access to Sebastian Stan, they might have went that way. But plans change.
However, I’m really beginning to dig the theory of the Red Queen being Grace’s mother and Alice’s sister…or any combination of the three. None of us really believe that Grace’s mother is dead. These guys are masters at wording things. All the signs from using the word “lost” to Regina’s quip about not abandoning family point to something more to that story. Maybe, though, Jefferson thinks that Grace’s mother is dead, just like Rumple did of Belle in “Skin Deep”.
Since Once:Wonderland is an open and shut story, I can see then just dropping clues about Grace’s parentage, leaving it open to be brought up on the “mother show” in Storybrooke.
Keeper of Rumplestiltskin's and Neal's spears and war paint and crystal ball.