In the art world there are many tricks and when one can think that everything arises from the genius of the artist, there is always an artifice behind and before the final result. In the creation of comics it is usually use the same character templates to change just the hand or the facial expression itself to save time creating a strip. If the result is excellent, there is no reason not to.
The same Disney has applied in those well-known animated films when they did not have the option of being able to deliver a job in a limited time. Apart from that there are some very beautiful animations that are used as a base to interpret other characters with them. But let's say, that the same key animations and collations serve to recover dances, gestures and different traits of such popular characters.
The dance of Sleeping Beauty in the castle is recycled in Beauty and the Beast and only that expert in animation you can realize that all animation work is traced. The only thing that changes are the two protagonists who dance, since the key animations are those that give all the meaning, realism and beauty of that dance.
Key animations are typically performed by the lead animators of a production. They are the ones that mark the most expressive features of an action and they are passed to the interleaves so that between two key animations, the X interleaves are made so that the animation is as smooth as possible. It is for this very reason that the drawing of key animations that usually show the trait or personality of a character or animation is relegated to the most expert animators.
In the shared video you can find how the animation itself is recycled, but with the difference of the use of different characters. It is not easy to create animations of such quality, apart from the fact that, as I said, if you have to deliver a job within a limited time, you can go to that reference to draw nothing more than some characters that are simpler than creating a whole new animation with your key positions.