To avoid confusing the masses:
Lookleft - it is cruise TAT/time/humidity that decides whether you get fuelfrost icing and being in Oz makes no difference. Per-Syd would easily have been enough.
Basil - the 'LOW' warnings have nothing to do with the pumps! You are confusing these with 'LOW PRESSURE'. Of course, there would also have been a 'CONFIG' warning there. That's 3 yellows they missed, plus a few checks.......................
Did they finish the crossword? With 4700 in ctre and having used 7600, I guess they were close to Syd and tanking?