A retired Qantas FEO recently self-published a book on the history of the Qantas Flight Engineers. I've not seen or read it but I'm sure there'd be a lot of info as to why there wasn't an FEO on Qantas' 767s and the industrial manoeuvring that took place prior to the arrival of the 762. I understand the author was one of the very last FEOs employed by Qantas and retired when the B743 was retired.