Stephenie Meyer by her own description knew absolutely nothing about vampires when she started writing and did zero research. I doubt that she had any idea where werewolf legends came from. That said, there are some Native American stories that are very similar to werewolves. The idea of a "skinwalker" shows up in some cultures, and the Navajo especially have a developed set of myths that has some resemblance. So if one felt a need to retcon this one would explain it with the natives simply using "werewolf" as the common English term for what they were.
(One could imagine fanfic where some of the werewolves are unhappy with this term and see using it as buying into European cultural imperialism or something like that.)
There are werecritters all over the place. I did a paper on "fantasy convergent evolution" in college and I was finding references to werecrocodiles and werebears and weresharks and random stuff, from all kinds of cultures that had no crosspollination.
In the vein of the Harry Potter and the Methods of Rationality discussion threads this is the place to discuss anything relating to Alicorn's Twilight fanfic Luminosity. The fanfic is also archived on Alicorn's own website <strike>(warning: white text on black background)</strike>.
Previous discussion is hidden so deeply within the first Methods of Rationality thread that it's difficult to find even if you already know it exists.
Similar to how Eliezer's fanfic popularizes material from his sequences Alicorn is using the insights from her Luminosity sequence.
Spoilers for the fanfic itself as well as the original novels need and should not be hidden, but spoiler protection still applies for any other works of fiction, except for Harry Potter and the Methods of Rationality chapters more than a week old so we can freely discuss similarities and differences.
EDIT: Post-ginormous-spoiler discussion should go to the second thread. (If you have any doubt on whether you have reached the spoiler in question you have not.)