Loveable Cats wrote: Well, that's easy. When he's smirking, he seems pretty evil and he also tries to kill The Road Runner.
Orange Mo already addressed question 2.
One of the "Laws and Rules" of the Road Runner cartoons is "The Coyote could stop anytime--if he were not a fanatic. (Repeat: "A fanatic is one who redoubles his effort when he has forgotten his aim." — George Santayana)." Granted, Michael Maltese said that he had never heard of the "rules" on the production of the cartoons, but that's not the point. Would you consider the Coyote's fanaticism a villainous trait? If your answer is "yes", why? For every one person who agrees, you might find one other who disagrees. Things like this prove my point exactly why some characters can't be defined strictly as a hero, a villain, a protagonist or an antagonist.
Since Sylvester was brought up, let's talk about him as well. I could argue that Sylvester is the protagonist and Tweety is the antagonist. For instance, Tweety is the antagonist for disrupting Sylvester's attempts at eating him. Of course, you may disagree. But what about Sylvester's roles in The Sylvester and Tweety Mysteries?
My point is that character morality isn't strictly black-and-white, especially in the Looney Tunes shorts, where there are many shorts where the characters attack each other to survive. That, among many other reasons, is why defining certain characters in strict protagonist/antagonist/hero/villain categories is pointless, in my opinion.