I think I'll start doing this.

And regarding #4, I think that a phone recording audio in a shirt pocket to aid later transcription wouldn't be amiss. Maybe putting the audio up online would, but in the news/reporting field it's pretty standard practice to have audio going while interviewing.

Also, if you [have/know somone with] a fairly "official-looking" camera with an externally attachable interview-style microphone, then you can go around and do some street spots with less awkwardness. When people see somone talking to a person on the street like that, they get the impression it's one-on-one. And if you approach someone, they'll be more likely to be comfortable with an interview-style conversation.