Not sure about BA and Qantas other than the obvious cooperation on the old Kangaroo route. BA might not get as much out of that as Qantas though (think BA shorthaul (feeder/distribution) network serves a continent of 350million people QANTAS serves a continent of 24 million. In addition both have their hubs at the wrong extremity of the intercontinental sections.ie you get off at the last stop on the line and retrace your steps in both cases.
BA Iberia is differnt, Iberia service wise are pretty grim in my limited expereince but they serve a totally differnt market to BA in Latin America where BA have virtuallya token presence and BA serve India and Asia which are the dark side of the moon for Iberia
As for BA-AA that just seems an invitaion for the EU nd US regulators to make life very hard fr both companies for many years before any possible synergies can come through
PB