I find this chapter less "dramatically built" and organized than the previous ones, at the same time it gives us many intelligence about the story, the characters...
The second sentence is so funny ("risen to the honour of knighthood by an address to the king during his mayoralty")...
Jane Austen was from good, ancient, respectable families and if in Persuasion, she laughs at those "old families" who scorned the "new ones" where there was merit, here she laughs at what could mean a recent knighting. At the same time, there is a respect to the institution, in Sir William Lucas' wanting to conform with nobility standards.
We know that Mr Bingley has aknowledged to a stranger that Miss Bennet was more beautiful than anybody at the assembly.
We know too, that Mr Darcy was addressed improperly (if you could confirm or invalidate the improperty?) by Mrs Long, and, contrary to Mr Bingley, did not pass over this. Mrs Bennet thinks he seemed angry because Mrs Long does not keep horses and carriage, but this doesn't seem very consistent with what we have already seen of him : it would have supposed being informed of the fact, which seems to me highly improbable.
We learn too, that Miss Bingley told Jane "that he never speaks much unless among his intimate acquaintance. With them he is remarkably agreeable."
We cannot know the accuracy of such a statement, but we know the inaccuracy of Mrs Bennet's deduction.
So, "an attentive reader" (which I was not at first reading, as I read the first chapters of Pride and Prejudice before anything else of Jane Austen, with language difficulties that made me understand little and ill) may already see two possible characters for Mr Darcy, one "of Meryton", of a proud, disagreeable man, full of disdain to who was not as rich as him; another of a man somehow awkward and irritable, but pleasant with his acquaintance., which could authorize a parallel with Emma's Mr Woodhouse.