Question: In the scene where Cheyenne visits Jill at the McBain's residence for the first time, he asks her whether she knows something about a man with a harmonica, although the three of them (Cheyenne, Harmonica and Jill) met earlier in the movie when Cheyenne tells Harmonica to "watch those false notes." Why doesn't Cheyenne just ask her for the man whom she probably still remembers from this event?
Answer: He meant what does she know about him personally. What's his real name, where does he come from and why is he so interested in everything.
Then he should have asked "do you know something about THE man with THE harmonica?" instead of "do you know something about A man going around playing A harmonica?" (time stamp 01:05:25 for the restored version) or am I missing something? He already knows that she has seen him because he was there so he could just ask "do you know something about the guy with the harmonica we met at the bar earlier?" I just don't understand why Cheyenne is using an indefinite article because he and Jill both know who he is referring to.
Answer: The movie was filmed at multiple locations in Spain and Italy, and also in Utah. Chances are they filmed out of sequence and made minor changes to the script later in the movie. There are many things left unclear in the movie, for example the same scene at the cantina/store, just after Cheyenne's crew shows up, he refers to Harmonica by his name when no-one said his name up until that point.