Final answer:
Carlo and Dulcibella were likely pretending to be characters from Commedia dell'arte, specifically The Doctor and Colombina, which are roles with distinct costumes and characteristics.
Step-by-step explanation:
Carlo and Dulcibella were pretending to be characters from the traditional Italian Commedia dell'arte. Based on the descriptions, Carlo might be pretending to be The Doctor, known as Il Dottore, characterized by his lack of actual knowledge and his prominent belly, which is often portrayed by a heavy-set actor in a black ornate pantsuit, with a white collar, black cape, and a half mask with a big nose and whiskers. Dulcibella could be taking the role of Colombina, the female servant who is known for her astuteness and wit, typically represented without a mask and dressed in a period-style dress, suggesting practicality and her servant status.