(Been having connection difficulties and only just managed to publish P after two days of trying so Quizis as yet only notes:)
Quizzing your characters is a good way to find out the secrets that only they and the hidden recesses of your mind may know.
They will not necessarily tell you the truth right away. Our brains love making patterns and finding the easiest way from A to B. As a cozy mystery author, you realize the straight shortcut may be the fastest but you are trying to construct a maze of misdirection to ensnare your reader. 🙂
Asking the right questions will let your characters help with this. The classic journalist’s questions are Who? What? Why? When? Where? and How? The signpost has added Which? and Whose?
They must all be answered. What the author has to decide is which questions and answers are most important for the telling of the story.