] Chapter 2

] There is a quote from P&P at the beginning of each chapter. Chapter 1 is obvious, of course, but I am not sure how the quote starting Chapter 2 applies.

In general I like the idea of quotations from P&P at the beginning of each chapter. But I don't think that most of them fit.
Chapter 1, as you've already said, goes without saying.
Chapter 2 is totally incomprehensible to me, too.
Chapter 3 means maybe that Elizabeth learns about how Mr.Darcy gets along with the London society and what they think about him. (But she learns nothing that could puzzle her)
Chapter 4: this is more clear to me. I think, it refers to the end of the chapter when they talk about the magic of love etc.
Chapter 5: I've no idea why a quote of Mary is used here but if I only regard the contents it simply shows that the Darcys go out.