I think Santa wears an IWC Portugieser Chronograph in team colours. I could see a chronograph being useful and Santa gives me IWC vibes.
I think Mrs. Claus wears a Cartier Santos that Mr. Claus bought her a few Christmas' back. He basically wanted an excuse to buy one for himself, so it was the old "Look! I bought us a matching set!" trope.
I challenge anyone to give a better suggestion.