#4: A Bird in the Hand: Dolores threatens to fire Bertie
#6: "Oh, Columbo, you are blind... You are SO blind," comes to us courtesy of Vivian Dimitri in "Rest in Peace, Mrs. Columbo", when she thinks she has poisoned Columbo with the jam.
I almost sure that #2 was in the end of Death Hits The Jackpot? In murder in Malibu they were watching women's underwear in the shop. Or did I miss something?