Thanks again for your help so far!
One question that may sound stupid: many hotels I've checked so far have a "children are not catered for" policy. What does it mean exactly? Does it mean that children are not allowed/welcome?
So far, we're looking at 4S in SYD, Sails in the desert in Ayers Rock and possibly Qualia or Lizard island.
Would the weather be hot enough at Qualia in August?