PreProduction Unit- Researching the Psychology behind Delaney and Abigail's relationship.

I have recently decided to spend some more time investigating the actual reasons that Abigail and Delaney may dislike each other. In a previous post, I explained that the reason I wanted the atmosphere to be tense between Abigail and Delaney, was because they were step-daughter and step-mother, and I really enjoyed the awkward dynamic of this relationship, as it somewhat reminds me of a classic fairytale relationship with an "evil stepmother" of course, in this situation, Delaney isn't truly evil.
I began my search once again using the internet, and quickly happened upon this article, entitled "The Real Reason Children and Adults hate their Stepmothers." I found this article very interesting, and found that it explained thoroughly the many reasons why Abigail may dislike Delaney, my favourite of which is "Loyalty Binds." The article explains;
"Many stepkids--and adult stepkids--suspect that liking stepmom would be a betrayal of mom."
This to me gives Abigail a legitimate reason for disliking her new stepmother. Afterall, Abigail's mother- (who she was particularly close to) has passed away, and therefore Abigail feels that she has an obligation to honor her mother's memory- by disobeying and disliking her new stepmother.
I have already begun to show this by having Abigail bring up her mother early in the story when she suggests that she should undergo the experimental vaccine by the research facility because her "mum would have at least wanted her to try."
I believe this further adds to Abigail's character as a "rebellious teen" and she can show her dislike of her stepmother by not doing as she is told,and maybe taking sly verbal shots at Delaney for certain things she does or enjoys. I experiment with this idea early in my script where when the discussion about the family not having enough money to pay for Abigail's private healthcare arises, Abigail suggests that "maybe she should get a job" sarcastically referencing Delaney and the fact she does not have a job.
Another aspect of that article that I feel could be related to Abigail and Delaney is the segment in which the idea of possessiveness and jealousy is discussed. This is a common trait in relationships between step-parents and step-children, and is mostly down to the ways in which step-children often grow to become familiar with having their parent all to themselves, and become agitated and hate-filled when the prospect of the parent having to be shared with someone else arises.
I feel this trait could also be used to describe the way Abigail feels about Delaney in so many words. I am not particularly sure how I will be able to to show this in the script itself, as it isn't something I feel would add to the overall plot, but it's something I definitely see the character of Abigail having as a trait whilst I develop her.