Tell you what, I'll wait a day or two and then post how we as a crew decided to approach each of these situations. If I think of any other scenarios, I'll be happy to post them...
Here's an interesting one that I encountered while flying for the airlines:
I was the FO on a flight with a very young crew. The captain had flown for the airline for 4 years and had just upgraded at 23. I was 23 1/2 (with 18 months of experience on line), and our FA was 19. Upon boarding at an outstation we were approached by an elderly couple, one of whom has serious concerns about our "youthfulness" and refused to board. How would you as PIC handle this situation?