At this point, I would like to address a more interesting topic:
In one conversation, if I recall correctly, Frank learns that Abby had at least mild feelings for him of a romantic nature BEFORE she learned that he was not her biological father. This is not surprising in that she was raised very sheltered by him, which is equally unsurprising given how her mother died. Then, recalling how she got Lilly to calm down back then (we still don't know the exact wording) I have to say that Abby and Becca definitely have some similarities. Both manage to "shut Lilly up" when necessary and both manipulate to some degree events involving Frank and Lilly.
In summary:
Becca: Manipulates various events and people for the good of the family. Also gives Abby some hints and clues about possible issues and whatever Abby is planning.
Abby: Also manipulates others to some degree, but less crassly and with far less experience than Becca brings to the table.
So in the pecking order of this family, I would put it as follows:
Frank
Becca
Abby/Lilly/Meiko
Becca could probably easily take the top spot, but she has no motivation to do so. She describes herself as a mixed type of dominant and submissive, though personally I would call her more subtly dominant. In comparison, her mother is more of the obviously dominant type, which I don't think needs any justification.
Abby is a mixed type for me, with the submissive part being a bit more pronounced, though she can definitely be different, as we saw with Lilly.
Lilly was more of the obvious dominant type at first, like her mother, though it was more because of her fears of abandonment and what Frank's presence meant. Now that she realizes she doesn't have to put up walls around herself, the dominant thing has definitely diminished.