After watching this I'm not really sure why Jessica is on the list. I assume we see more later but my impression of this one is that she doesn't really deserve to be. Sure, she hurt her by not telling her she was in a relationship with Alex but that just doesn't seem like a good enough reason for me.
This is what I know him from too. I can't help noticing Jack-isms from him and thinking "wow, I see why they cast him as Jack's son back then!". I actually quite like him in this although he really needs to watch where he's going otherwise I imagine the show ends with him dead because he got hit by a car.
The funny thing is, I've read this book, although it was years ago, and I barely remember any of it other than the overall premise.