1)
Why is she called Shifchas Rachel (and similarly regarding Zilpah in the next verse)?
1.
Ha'Emek Davar: She acted towards Rachel like her Shifchah, and so Zilpah acted towards Leah.
Why is she called Shifchas Rachel (and similarly regarding Zilpah in the next verse)?
Ha'Emek Davar: She acted towards Rachel like her Shifchah, and so Zilpah acted towards Leah.