I believe that number 2 (the one about the car) is (I think) from "Death Hits the Jackpot" when Freddie has ordered a ritzy car and had a picture of it. This scene in which we see Columbo's car outside reminds me of when another used car salesman says to him, "I'll give you $80 in a trade Lieutenant." Something close to that effect anyway.
Anyhow, I think I answered #2 correctly. The other ones I'm not sure on.
Everyone did well except nobody got #5. It ws a toughy. When Columbo first showed up at the house in "It's All In The Game" he had a nice pair of slacks on, raincoat (obviously) and a pajama top! Go figure. In fact, he makes certain to button his raincoat before confronting Faye Dunaway, who gave a really good performance and who is very sexy looking in that red dress!!!