Symbolism, Imagery, Allegory
You need to be packing some serious heat to take out the zombies in this book, and the weapons a character carries tell us a whole lot about who that character is.
The Bennet girls are highly trained in the deadly arts, and so they know how to use all kinds of different weapons. Daggers, muskets, and Katana swords are all part of their repertoire. Being versatile is pretty important, because a lady can't always carry a weapon around in public:
They set off together, armed only with their ankle daggers. Muskets and Katana swords were a more effective means of protecting one's self, but they were considered unladylike; and, having no saddle in which to conceal them, the three sisters yielded to modesty.(7.31)
Wouldn't want to be unladylike while beheading zombies, right?
Mr. Bingley, on the other hand, has a "French carbine rifle" (3.4) that he carries around, but it's obvious that he doesn't know how to use it. Mr. Darcy is usually spotted with either a sword or a musket, and he's able to handle both well. Too bad he's such a jerkface:
Though [Mr. Bingley] lacked Mr. Darcy's proficiency with both sword and musket, such amiable qualities must speak for themselves. What a contrast! Mr. Darcy was the proudest, most disagreeable man in the world, and everybody hoped that he would never come there again.(3.7)
Hmm…not sure that everyone would prefer Mr. Bingley's smiles during a zombie attack—but we digress.
Lady Catherine is so confident in her abilities she doesn't even carry a weapon. Of course, she also travels with an entourage of ninjas, so maybe those guys are her weapons. Rich people always have the best toys.
How each character protects him- or herself says a lot about that character's social class and gender, and about how that character moves about in the world of the novel. But, in every case, it's pretty much just bad news for a zombie.