I don't really disagree with much of what you have written, Peter, but I would suggest that there are different ways of knowing a person well. There is knowledge that comes through shared experiences over time, and then there is knowledge that is gained through extraordinary shared experiences. At Hunsford they each saw each other at their worst, and then later could see (over time) how the other had reacted to that emotional blowout. Elizabeth had the benefit of Darcy's letter, in which he laid a great deal of himself open to her, and she also could see much of his character in his gracious welcome at Pemberley and his efforts to recover Lydia.
The novel tells us that Bingley and Darcy had a steady friendship, which implies to me that they'd been friends for years. They apparently spent weeks and even months together, and yet at the time of Darcy's second proposal, Bingley didn't know about Ramsgate or Darcy's first proposal or that Darcy hadn't told him Jane had been in London or that Darcy had rescued Lydia and why he had done so. He may not even have known Darcy's whole history with Wickham. So at that point, is it accurate to say that he knew Darcy better than Elizabeth did?
