For me, It's not that the mom is favoring ashley way too much by intent, it is just that the "mom" knows or is aware of "the plot" or "storyline" she's in so she is preparing her and the rest of the daughters to all have a good ending at their end.
But because things she expected did not exactly happened like The Fairy Godmother's presence or Cinderella with the Prince, she remains hopeful that the main plot is bound to happen with a change, her daughters will also find their good endings.
These are all my opinion
idk why but i still feel like the mom is favoring ashley way too much. maybe bc she is the cinderella of the story, but it doesn’t feel right either way