Does the practice of creating U class "Ghost Segments" in the booking have anything to do with the upgrade Wait List?
Is the creation of a "Ghost Segment" a good sign or do they do that whenever an upgrade is requested?
If I have an Australian address in my profile, am I more likely to get an upgrade on the ex-Sydney leg?
Yes. From my experience, I had some U ghost segments after requesting an upgrade too, but never had one when my requests were immediately rejected.
Yes but you might wait forever... If you are Gold or Platinum you should give them a call and ask if they can open an upgrade seat for you.
I don't think so but who knows ? QR has so many secret rules...