According to an interview with Neil Druckmann, Cassie Drake was originally going to be a male character, but this was change their female lead character concept artist. The artist wanted Nate & Elena's child to be a girl, and Neil was convinced by her decision.
In an interview with Neil Druckmann, it was revealed that the "Doughnut Drake" skin would not return in Uncharted 4, due to being offensive to people who are overweight.
Standing still after a cutscene in chapter 11 will give you the achievement "Stage Fright". This is in reference to Sony's press conference at E3 2015, when a glitch rendered Nathan unable to move in Sony's demonstration of the game.
Drake's costume went through a number of different designs, all specifically designed to not stand out. The designer wanted to have all of Drake's accessories and his outfit to not distract from the motion actor's work and Drake's facial features but also to portray that he had not been going on adventures for some time.