I actually fell for it so hard that she wasted no time in devaluing me and I became obsessed trying to undo my screw-ups and win her favor again because I was sure she's "the one."

Of course, I now realize her "love" for my sons is because they are great athletes and great boys and she wants them to rub off on her son (9 years old) and her relationship with them helps her to keep up the "pure" facade. They are also very well known because of their athletic prowess, so I'm sure she maximizes on this as well.
About a month ago, after falling for her and trying for months to win her over, I finally just told her "either we will be more than friends or nothing" and professed how much I was in love with her (which I now know probably repulsed her) I walked away. She even had the last word in our final argument when she told me in a text "Just leave me alone. We are not friends anymore." Reading these forums I figured letting her win would be the end of it, and for a month it was.
Four days ago her grandpa died, and she made a huge spectacle of it on Facebook. She created several posts, maximizing on people's sympathy and I actually felt bad for her. She was always good at making me feel guilty. I just sent her a simple text "Sorry about your grandpa." A minute later she replied with "Thanks" and I thought that was the end of it.
Two days passed and I got a text from her yesterday morning asking if I could acquire some info for her; a boy who is much older than her son was bullying him on the school bus. I got the info for her and she replied with "You are so awesome....thank you....I miss you like crazy....but the boys more.

Absolutely fascinated by this creature I decided to carefully see where this would go. Until her grandpa died, our last couple of weeks were bitter and hate-filled; how in the hell could she "miss me like crazy" after only 4 weeks? Of course I know the answer. I responded "Yeah, I'm sorry things got complicated between us. Maybe we can hang out sometime." I made sure not to apologize or blame her in any way, and kept things intentionally vague.
She responded with "I would love to!!!!

I'm going to keep playing cool and see where this thing goes. If I never hear from her again, fine. I've gotten used to being without her and I no longer care about her the same because I know what she is. I'm just fascinated by this bizarre disorder that I had never heard of until about 5 weeks ago. I don't mean to disrespect any of the HPD sufferers by treating this "friend" as a kind of lab rat, but it is exciting being able to predict what she will do, and now being able to make sense of her behaviors that had me so confounded before.
I'll keep you all posted, and if this thread gains traction I'll delve into specificity regarding her past behavior that led me to this board. Thanks for letting me get this off my chest.