Curly's wife is certainly an example of a "femme fatale" or temptress. This is a seductive, sometimes mysterious woman who charms other characters, often leading to disaster. The Biblical Eve is sometimes considered a femme fatale because she lures Adam to try the forbidden fruit, which leads the two to be expelled from Eden. Curly's wife talks and sometimes flirts with the other ranchers and this can unleash Curly on them. In the end, she lures Lennie like a siren, persuading him to pet her hair.
If there is a hero in this story, it is George. He is the one who protects Lennie from the rest of the world. He does so out of obligation, then duty, and then because he genuinely cares for Lennie. He is also a father figure or mentor to Lennie in this way.
Lennie, as a result of his mental state and occasional unintentional violent episodes, is an outcast. He is also a gentle giant: innocent but powerful. In the end, he is the scapegoat. This is a character who takes the blame (or is blamed) for things going wrong. The scapegoat can also be a character who is sacrificed. Lennie fits both of these definitions.
Curly is the villain. The villain, also often called the antagonist, is evil, self-involved, duplicitous, and manipulative. Curly constantly provokes others and tries to start fights. He thinks only of himself.