:It'd be off topic whether you put the info in the article or linked to a Harry Potter wiki. Use some common sense. These characters and themes appear in literally hundreds of thousands of fiction books: that's not notable, and we sure shouldn't clog up the article with links to websites discussing all of them. If Harry Potter discusses any of these things, put it in a Harry Potter article if you think it's important to readers of Harry Potter, but do not put them anywhere else.