Final answer:
The line includes both personification and alliteration.
Step-by-step explanation:
The line "They're probably drinkin' coffee and smoking big cigars" includes both personification and alliteration. Personification is a figure of speech in which human attributes are given to non-human objects or ideas, and here the line attributes the action of drinking coffee and smoking cigars to an unspecified group of individuals. Alliteration is the repetition of consonant sounds, and in this line, the repetition of the 'co' sound in 'coffee' and 'cigars' creates the alliteration.
Learn more about Personification and alliteration