If I got an offer in UNSW, How can I know whether I am qualified for UWS or UoN? Do they inform me?
No they do not inform you. I'll give a direct anecdote: last year I put UQ at pref 1 and Griffith pref 2, got a place at UQ, my ATAR 99.80 would have got Griffith as well but no words from either QTAC or Griffith. Logical reason for this is you've got your first (or higher) pref you shouldn't need to still be concerned about the lower prefs' outcome.
I could have accepted the UQ offer then moved Griffith to higher pref to get it considered for 2nd round place offer, but I didn't (why I count Griffith as half an offer haha).