Protagonist for the main character. Antagonist for the character opposing the protagonist (not necessarily evil.) Hope this helps!
No. It's plagiarism, so don't "borrow" a character or storyline that you like. You could have a similar story, but never make it so similar that anyone can say "that's just like this other story!"
whichever one you think
novels are evil little books that teachers make you read for torture
Yes. Any used outside information should be enclosed in quotation marks and cited in the text as well as on a Works Cited page.