When you really look at the sisters' personalities and actions in story, they almost parallel Dahlia and Iris. With Morgan being a parallel to Dahlia of course but Misty being a parallel to Iris.

The parallels with Morgan and Dahlia is pretty easy to see. When we first meet her she gives off the impression that she's this strictly traditional yet caring guardian of Maya and Pearl. However as we learn not long after that this persona is actually a facade. Morgan is truly a vengeful bitter person who is willing to hurt and discard her own family for her own ego and selfish desires. Just like her daughter, Dahlia

On the other side we have Misty and Iris. All we knew about Misty throughout the trilogy is that she had abandoned her family and clan and went into hiding because she had felt great shame and heavily blamed herself for the Fey name being ruined. Even if the circumstances were not directly her fault. Similarly to Iris who blames herself for the consequences of Dahlia's crimes going wrong and is so filled with guilt over lying to Phoenix about her identity during their relationship, she runs back to Hazakura Temple to hide from him. Even if her decision to pose as Dahlia was to spare his life and prevent her sister from getting into more trouble. However, even with Misty's morally questionable choice to leave her daughters without a mother, she still cared deeply for them and, like Iris, was a kind loving person who was willing to sacrifice her life for the people she cared about.