For me, I picked what I did based on both physical traits and personality quirks.
Main T has the beard and likes all things related to the ocean ---and I love this pic to show his huffy indignant side. (this isn't my T but there is a slight resemblance!)
CBT T has the curly dark hair and goatee, and an impish, boyish sense of humor and bombastic enthusiasm. And a little animal allure too