Let's say I make a character named Lila. There is another author that had a character named Lila but I make my Lila very different from the other authors. Is that copyright?
Well unless you are using a specific last name that appears in another authors book then its definitely not going to be a big deal. Generally though I like to wait until a story is finished before I name the characters because sometimes they end up naming themselves.
Many authors have taken up Sherlock Holmes and have written stories based on the original. The same is true of The Wizard of Oz.
General names aren't patented - you can use them whenever you wish.
Yep, its just a name, no one has rights to a name..