Not sure if they are traits but, for example, Caprice has a card "Why are you doing this? I'm your sister!" and at the bottom it has a Light section "Caprice gains one Trauma" and a Dark section "Caprice discards all of her dark cards and gains one betrayal". To play this she must enter a location while she has more dark than light cards in her hand and it is a Fight/Nightmare card.
So, if I play this on her, she gets to choose which path/tactic to take, Dark or Light, correct? It has nothing to do with the location of her twilight marker on her detective card?
Yes, the target of a "fight" gets to know the results of the light/dark path outcomes before making the choice. It's in the Official FAQ.