Just a thought, but if they don’t have the 2nd sem results by 17 Dec, given that UNSW only looks at GPA when 0.75+ FTE has been completed, could the interview be based solely on ATAR/UCAT in that case?I have read somewhere the TACs (or at least UAC) will do a final round of ATAR/GPA update early January to be ready for offers calculation. Thus UNSW says your academic results must be available by early January to be considered.
As for interview selection my guess is when UNSW releases invites on/around 17 Dec, if your year-end results are not yet available they will provisionally use your 1st semester results. If that's not enough to get an interview but after the UAC January update (with year-end results) you are high enough they will invite you to the interstate round. I vaguely remember it has happened like that.