Factual error: When Bella is driving back from Seattle, the speed limit signs say 80. There is no 80mph speed limit road between Seattle and Forks; the movie was filmed in Vancouver and the sign is, in fact, in kph. (01:04:55)
The Twilight Saga: Breaking Dawn - Part 2 (2012)
1 factual error - chronological order
Directed by: Bill Condon
Starring: Kristen Stewart, Robert Pattinson, Maggie Grace, Taylor Lautner, Peter Facinelli
Continuity mistake: At the end, when Bella is thrown into Edward, she is wearing shoes with a heel, but a few seconds later she is wearing regular boots. (01:32:50)
Bella Swan: You nicknamed my daughter after the Loch Ness Monster?
Question: Can vampires and werewolves be killed or injured by anything other than vampires and werewolves?
Answer: Sure. The problem is that these films portray vampires and werewolves as having super-human abilities, so it'd be significantly harder for a regular person to kill one. But nothing about the films seems to indicate it's overtly impossible.
Answer: Aro also makes the argument that for the first time in our history humans pose a threat to our kind with their weapons that can destroy us. Theoretically any weapons that can tear apart and/or burn the vampires would work. So, yes, things other than vampires and werewolves can kill the vampires and werewolves.