Yes on all counts. The cartridges were machined brass and take special-size caps to cycle the action.
Please provide a link. I only found reference to airsoft products.
Never mind, here’s one:
https://www.google.com/amp/s/replicaweaponry.com/amp/blank-guns/
I do stand corrected! It makes you wonder why these types of products are not more often used in Hollywood.