Disney employees must strictly follow meticulous rules as ‘cast members’

There is a height requirement for every character. Disney princesses must stand 5’4″ to 5’8″. Those who did not reach this measurement can play other characters.

Aside from the height, there are also certain rules when it comes to the physical aspects. However, this has been updated in April 2021 in order to welcome “greater flexibility with respect to forms of personal expression surrounding gender-inclusive hairstyles, jewelry, nail styles, and costume choices.” 

This was stated in the blog post of Josh D’Amaro, Chairman of Disney Parks, Experiences, and Products.