Can I say "replica" instead of "prop"? Or do they have difference nuance?
Answer from a Native speaker
A "prop" is an object used on stage or screen by actors during a performance or screen production. For example, the wands seen in the movies would be considered props. A "replica" is something else entirely - it is a copy or model of something else (oftentimes a smaller version of the original thing). If the wands in the exhibition were replicas, that would mean that they were copies of the original props used in the movie. Ex: A museum got scammed into buying a replica of a famous painting. It was just a fake item and not the real thing. Ex: Many famous movie props have been auctioned for charity in the past, including Harry Potter wands.