In case anyone's curious, I picked the flight. It was delayed ~15 mins due to ATC, but I still arrived earlier than my mother's flight, so it was all good. Conversely, my friend took a ferry back to ATH that day and ended up delayed 2h, so it's really luck of the draw. I didn't see any additional ferries added to the schedule in the end
... Now the 3h we spent waiting in ATH for her luggage is another story
