Dr. Hopper's dog, Pongo, is a direct reference to One Hundred and One Dalmatians (1961), the Disney animated film. In the film, Pongo was the male dog owned by Mr. and Mrs. Radcliffe.
The Welcome Home sign hung up at Granny's for the party is the same sign used to welcome Mary Margaret home (after Kathryn is found alive), with a small addition of "and Emma" added on with another sign.
The object/animal/person in this episode is Pongo.
Paul McGillion (Knave of Hearts in the previous episode) and David Nykl (the fisherman at the beginning) starred together in Stargate: Atlantis.