Once you are done accusing everyone in the dining room, exit and then enter the living room. Felicity Flitt will be looking inside of a dress up kit go ahead and inspect the kit. Use the Bow tie, Top Hat, and Heart Glasses. When the duo come down do what you must to get the motive and weapon before you continue. Once you have the Motive and Weapon, go get the Police Sketch and the small Sailor hat from the Kitchen (After you tell Constable Dibbins to question Major Crum), and head back to the living room and inspect the dress up kit, and select the Spiked Collar, Fez, and Prince-Nez Glasses. Then either walk out the room and back in or just wait a few seconds and the duo will leave. Inspect the kit once again, but this time select the Diamond Collar, tiara, and the movie star glasses. Once again either leave and come back or just wait. Time for the last selection. Inspect the kit and select bandanna, sailor hat (after using the one in your inventory on the slot), and trendy sunglasses (after using the fashion magazine on Felicity).