I have never known a show to put in a filler actor, but i think it is possible. It may just be that this is their take on the Queen of Hearts making her quiet instead of loud just to be different. Though the dialogue where Jefferson says something like do you know what she does to people and Regina says better then most or something like that. I should look up the dialogue. It just really made it seems like Regina was referring to someone taking hearts and she does know what it is like for her mother to take a heart better then most. The thing is that when i think of what the Queen of Hearts does it is cut people’s heads off and not take people’s hearts. I still think it is a really good theory.