It's a nice idea, but I think if you find pun in one, you have got to find a pun in a lot of them, before you discover anything significantin JA's writing method.

Well, perhaps; I personally don't think you really have to take such an all or nothing approach, or imagine that this might indicate anything significant in JA's writing method (I really don't think it does). I had in mind more that these two place names, Longbourn and Meryton -- but possibly Netherfield too -- might simply have been some sort of private family joke. That's more likely in P&P than in any of the others, because of the circumstances of its composition -- written fairly early on, and extensively read, and read aloud, for years in the circle of family and friends, before being revised for publication. Also, I think, Meryton could have both been Merry-town (something rather Bunyanesque there?) and an alteration of Cheriton. At long-borne Longbourn, each member of the family has something to bear from some other member, but perhaps Mr. and Mrs. Bennet in particular from each other; Netherfield -- far away or too far, it is hoped, for Jane easily to return.