Good for you!
I think not doing 20 questions right away was a good idea. Let her know you as a human being first (and vice versa), not get put on the defensive with an interrogation.
Basically, if there are little discrepencies, they will come up on their own. Or maybe just knowing the two of you talk with inspire Sundance to be honest with both of you.
I bet he was shocked! Honestly, that might be enough to rock his world and his thought process a bit enough to reevaluate how he's handling things. But nice to know that most of what he said was true. At some point maybe expressing that you were starting to go off the rails with believing him because of the lying thing, so reining that back in so that you both know you can trust each other at their word will be a big help for both of your peace of mind.