Sounds to me like they had a stuck wheel brake from the get-go. They reported hot brakes and got out of line while taxiing out. Then got back in line and attempted takeoff. The Airbus aircraft have brake temp indicators and some have wheel brake fans to cool them off.
I've never personally heard of having hot brakes while taxiing OUT for takeoff but have heard it taxiing in after landing and having used the brakes for that landing.
Capt737AA