Scenarios or "Behavior" questions elicit specifics usually. Give people a few "What would you do in this instance?" questions plus some "Tell me about a time when..." questions. I always liked to ask: "Why do you want to work with us?"
To determine how self-aware they are ask "What do you consider your 3 greatest strengths and why?" "How do you think you would you apply those strengths in this position?"
When you ask behavioral or scenario questions (ask the same ones of each candidate) you should be able to elicit important information that will help you decide.