What are some good names?

Depends on their character. Is the witch bubbly and sweet, or more like the wicked witch of the west? I think it would be cool if one of your characters has a totally different character than you would expect from a monster. For example, if the witch were sweet, give her a name to match her character, an innocent name like Juju or Polly. A witch playing the bad guy would be more like a Domenica or Sinthia. Play around with it. There are millions of possibilities. Have fun with it, and hope I helped!