Ha ha nice videos. GSD puppies by adult dog standards have no manners, and always try to push their limits as well as their chances. I'd recommend wearing the puppy down some first before introducing them to adult dogs in the house hold under 100% supervision.
Let the adult decide when it should be over. My lab wanted nothing to do with the puppy till he was 4-5 months old had picked up some manners and then they started to play together. I still keep them mostly separated although they get a long great now.