I recently came across this interview of two Disney artists on how they animated the characters in Frozen 2. I found several of their comments really interesting, such as how they rely on hand-drawings and acting out the scenes themselves in order to come up with realistic animations. They also noted how subtle motions, such as breathing and the movement of the characters’ toe joints can drastically change how realistic the characters look.
How the ‘Frozen II’ Artists Created Believable Emotion Through Animation