We Need to Talk About Kevin question

I honestly think that yes he kept Eva because he felt somehow she would understand his need to destroy others. I think he just started to enjoy torturing people in general.

I think he sort of explains it in his interview, that he wanted to become the watchee instead of the watcher(audience), and his mother was the audience. I truly believed that all he wanted was her attention, and she spurned him, so he resulted to negative attention. I think ultimately the reason he killed Franklin and Cecilia is that finally, her attention would be solely on him. He mentions that he would go into the bookstore to look at her books, and he even had her picture on the wall.
As for his classmates, Eva also sort of explains it that, Kevin desperately wanted something to be passionate about, but I don't think he was capable of it, so he was envious and jealous of people who did have a passion.
Ugh, there are sooooo many different ways to look at this book, the discussions are endless I find!