1. A risk of booking separate itineraies (with separate airlines).
2. I doubt the first Captain decided to cancel the flight lightly, I am sure he was guided by what the company said, and what the procedures said, so it seems silly to blame one individual
3. I also doubt the second Captain simply taxied to any old gate he came across, and said "hell yeah, that'n'll do".
4. Don't trust the French.
5. What's modified business class?