Hi there.
Not sure what 6'3" is in cm's but most airlines have height restrictions - usually 162 - 183cm.
I'm pretty sure that you need to be a pilot with an ATPL to get a job with an airline in Aust...perhaps you should post that question to Dunnunda & Godzone. Lots of pilots there!
As for being "bonded" to the airline. Some airlines do it & others don't.
Pays and rosters also vary from airline to airline.
Good Luck with your quest!