Amy definitely fits into these categories:

Predisposition - "people who are different, unpopular, or great sinners are apt to return from the dead. (P. Barber)" "one universally recognised member of this category would be the suicide. (J.A Thilmany)" - Amy, the local mad girl, who both hints at suicidal thoughts during her time as companion ("Listen to me. I understand. Really, I do.") and actually commits suicide, on various occasions (Amy's Choice, The Girl Who Waited, The Angels Take Manhattan) AND comes back from the dead in some form or another on those occasions and others....if anyone matches the description of those predisposed to vampirism, it's her.

Predestination - "frequently people become revenants through no fault of their own" "a revenant is born with two hearts, one of which is dedicated to the destruction of humanity." (P. Barber) - those predestined to become vampiric are often people who come from "abnormal" parentage, Amy's parents Do Not exist when we first meet her. And, even when they have been brought back, they only show up in part of one episode before becoming non-entities again (it's a flaw in the writing more than anything else but it still emphasises her "abnormal parentage"). "a revenant is bloody and blood is red; redness, therefore, must predispose toward vampirism." (P. Barber) - The redness is an obvious link: red hair, red clothes, the red houses, the apple....she's red.

Events - "people become vampires by being bitten by one." (P. Barber) - She's bitten by a Saturnyne Vampire in The Vampires of Venice.

Nonevents - "Lack of burial is itself, then, a sufficient reason for murder victims and suicides to become revenants" "another common explanation for their transformation is that they have not lived out their allotted span of life." - In most of Amy's deaths, she goes unburied. Again, this is usually because she's due to be revived but that only really emphasises the connection. In the one case where she is buried, TATM, she's a victim of the Weeping Angels; their whole thing is feeding off the potential life that their prey leaves behind, the life unlived, thus, she does not live out her allotted span of life.

So, Amy fulfils each category of the causes of Vampirism.

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She also displays various "vampiric traits" - the main one being the idea that those afflicted with vampirism become locked in one phase of their life/body, never able to grow up past the point of their turning. Similarly, Amy never quite moves past her garden, her waiting. A big component of her character is that she can't let go of the Doctor + her childhood. Though the writers claim she does, they never go past just saying it, we're given very little reason for her abandoning her faith in the Doctor. In fact, they often emphasise the opposite (the shot of her waiting at a window at the end of The God Complex, the S7 promo where she's pictured waiting at a phone for the doctor to call, "is it bad that I've really missed this?" in AoTD, "I can't not wait for you." in DoaS.). It's arguable that she remains trapped in this phase of waiting/hoping for 11's return up until her death. Even in some of TATM's deleted dialogue, she expresses a worry that he'll stop coming back for her out of boredom. Just as a vampire is stuck in the body that they had at the time of their turning - Amy is stuck waiting for the Doctor for her entire run as companion.

 Another of her vampiric traits is summed up by J.A Thilmany in “Draining life forces: Vampirism in Emily Bronte's Wuthering Heights”:

 Amy’s last proper appearance on the show takes place inside the TARDIS, though she dies outside of it. She returns to her home as a ghost, or a daydream.  A slightly different take on the above trend is presented by Nina Auerbach in “Our Vampires, Ourselves”:

 The “confined space” in Amy’s story is the garden that she constantly returns to. It ties in with her vampiric inability to move on/grow up as the garden is the home of her waiting. She can’t escape “the girl who waited”, because she often doesn’t try to - instead choosing to return to the garden (as she does in TGWW).

 Returning to her final scene on the show, her appearance right at the end of 11′s life presents another vampiric trait. The scene echoes one from TATM where Amy is present for an older Rory’s death, holding his hand as he dies.  In both instances, Amy is the figure marking the death of one of her loved ones, mirroring this trait referenced by Barber:

And again by Thilmany:

 Amy’s presence in both scenes is presented as the thing allowing Rory and 11 to pass on. They see her again, meaning they can die somewhat peacefully. Obviously, this isn’t a feeding as presented by the two extracts above but the scenes present something equivalent to that.

 Another feature of final the scene that presents a vampiric trait is the fact that it’s not actually Amy, the figure is strongly implied to be a figment of 11′s imagination. This mimics another idea outlined by Barber:

 Amy is still buried in New York, but an apparition of her is in the TARDIS performing her equivalent to feeding.

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 Having outlined how Amy fulfils both the causes of vampirism + the traits of traditional vampires, the last thing to talk about is the transformation that is characteristic of vampire mythology, particularly the transformation presented alongside women vampires.

 As most of Amy’s vampiric traits link back to the Doctor, it makes sense to argue that his introduction into her life is what marks her “turning”.

 When 11 meets her, she’s a child, and so she’s “pure” and “virtuous”. She’s the fairytale girl. She’s not entirely “perfect” and she presents the traits of those predisposed to vampirism: she’s from abnormal parentage/familial history (”I don't have a mum and dad. Just an aunt.”), she’s othered + different to the residents of Leadworth (”the Scottish girl in the English village”) and she presents a connection to supernatural (or preternatural) forces (”at night there's voices”).

 So, she enters the story as the fairytale girl, predisposed to the vampiric condition. The Doctor makes a promise and then he leaves, having set the change in motion.

 The next time we see Amy, she’s become the corruption of a fairytale, just as women vampires often represented the corruption of traditional femininity. She’s changed her name, dubbing it a “bit fairytale”, she’s noticeably more volatile and violent than her 7yr old self and she’s overtly sexual, a trait that is common in most women vampires.

 This transformation of “purity” to “corruption” (please note that I use these terms with heavy amounts of distaste) is extremely common in stories about woman vampires (the biggest example being Dracula’s Lucy Westenra). And so Amy’s movement between the two, though it’s the product of age in the narrative, does mimic a traditional vampiric transformation.

 The Girl Who Waited only further emphasises the idea of the fairytale corruption + vampiric transformation.

 Amy’s base in the episode is described as a lair and the HandBots view her as diseased + in need of treatment. The lair calls up connections to monsters + wild animals but also refers to the Scottish term for “a burial plot in a graveyard” - both of which are spaces that vampires traditionally reside in.  The idea that Amy is “diseased” falls in line with the concept that vampirism is an affliction or virus rather than a transformed state. Throughout her time as companion, Amy is shown to have been subjected to various forms of involuntary treatment (highlighted in this post by @mikaelson) furthering the idea that she’s viewed as sick despite not being unwell at all - just different or “transformed”.  Her death in this episode also highlights a vampiric state, as she stands outside the TARDIS doors, unable to enter without being allowed in, invited in. 

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