With regard to CASA and Maintenance and designated positions.
It is all laid out here in the Guidance material for Part 145 AMC
http://www.casa.gov.au/wcmswr/_asset.../amcgmp145.pdf
Ultimate accountable manager should be Joyce as CEO - but that may have been delegated to GM Engineering.
From there depending on the structure there will be responsible managers - probably GM Line maintenance and GM heavy or whatever they call those positions.
Below that there is no real requirement for managers to have any specific qualifications - as long as they are not deemed "responsible managers" as per Part 145 in the company structure.
But - the ultimate requirements will be laid out the Qantas Engineering Part 145 MOE - that will list the positions and requirements for each of those positions.