C is indeed from Blackout.
As for the dog in photo A, no, he didn't wander over from the Columbo set--unless Peter Falk and his trusty companion were also on location in . . . well, it's too early in the game for hints.
But I can guarantee you'll be amazed at the menagerie we assemble in this series of brainteasers. So far we've got a basset hound looking doleful, little piggies (presumably on their way to market), a horse of the day, an elephant doing whatever it is elephants do (although probably not "jumping up and down for you," as the song would have it), and a flock of pigeons consorting with a secret agent.
Lots more critters, both commonplace and exotic, to come. Stay tuned.
Regards--