That being said, let's remind ourselves of what roles the two versions of Katie play in the strip. Liz, as we all know, was sort of a clingy, whiny, fearful annoyance desperate for attention that her mother begrudged her. We also have to factor in her need to trade on her looks, her inability to get along with Mike and her being somewhat oblivious to her surroundings when reminding ourselves of why it is that the older avatar more or less immolated herself on the pyre of the Settlepocalypse in an unavailing attempt to win the approval that just isn't in her mother.
We also have to remind ourselves that April was held down, ignored, lied to, given bad or evasive advice, willfully misunderstood, mocked and mistreated at every opportunity by a woman who took pleasure in misreading her. What's more, we are clearly meant to not only not see things from her perspective, we are meant to believe that Elly was backed into a corner and forced to take the path of least resistance.
The only conclusion that makes sense is that depending on Lynn's whims, Katie was either Liz or April. When Katie was following along the life path that most meshed with her mother's need to be paid back for what quitters and wimps who don't understand how life is a "moral obligation", she was the Liz who made Paul up so she could date a sunken-chested adulterer but when she disappointed Lynn by displaying free will, she was the spoiled, selfish little princess that only seemed to exist in the imagination of an entitled dimwit who refuses to admit that she was ever cruel, sullen, selfish, vicious and unfair.
Given that we have a lot of duplicated avatars, this battle of the archetypes probably extends to other characters. As by way of example, the Aaron who lives in Vancouver and doesn't want to be joined at the hip to a woman who doesn't know him despite having given birth to him is Weed while the part who listened to her is Mike.