And because I hit "enter" too soon...s
"Honorific" being such a general term is what make it potentially much more appropriate for your story. (It depends on how your language works.) A title is much more specific.
You can describe a verb affix as honorific. You can describe a pronoun as honorific. You can describe the someone's speech as honorific. And so on.
If you just want a label for the words in your language that people address respected others by, then I agree that "titles" is better. But it doesn't work for things like polite verb endings.