Pride and Prejudice and Zombies is not necessarily an allusion, though without that literary device, the form itself would not exist. Technically, it’s satire. Sort of. It’s really fan fiction.
The best part about a zombie story is the zombies and the survival or lack thereof. The best part about an eighteenth century novel about manners is the exquisite agony of the nuance of every breath, every bat of a eyelid.
If you choose to launch yourself down the rabbit hole of novel genre mash-up, I would caution you to be an absolute expert on each genre expectation first. For example, in Pride and Prejudice times, there is a mannerly way to press the big red nuclear button: the cut direct. If the cut direct is activated, the person to whom the maneuver has been deployed against no longer exists. This person will not be acknowledged in any way, shape, or form. It’s like a one-person ostracization in a public room and believe me, if anyone has mean-girl shunned you in public, everybody and their second cousin knows it.
So if you were to attempt a genre mash-up involving a comedy of manners and oh, zombies, for example, the understanding of those manners should probably be on par with the fan who buys grocery sacks of romance novels weekly or people Just Might Talk. For more about Pride and Prejudice and its intertwining themes with zombies, check out this amazing haiku review at Dear Author.