Re your LAX connection: are you booked on 1 ticket? If so you have absolutely nothing to worry about: wherever it is you're ultimately going, you'll get there between BA, AA, Aer Lingus, Iberia, FinnAir, Alaska, and even United if that's what's necessary. I was on a delayed flight in to Chicago last week and passengers who'd missed their connections had already been rebooked on to services the next morning and had rooms booked in hotels for the night.

If your specific flight is cancelled, or some other sort of involuntarily denied boarding scenario occurs, you'll get put on to an alternate service as quickly as possible.

Relax and enjoy your flight.