The average to get into the jd program for the last several years has been a wam of 75ish for a full fee position and 80+ for a csp supported place. The lsat scores were around 160-170 (usually 70th percentile). All said, entrance based on these scores will be vey tough, especially since it is very difficult to maintain a wam of 80 for your 3rd/4th yr level subjects.
My advice is if you are passionate about law and you want to complete your law program at either monash or melb and you do not get the required atar - start an undergrad degree at any victorian university (does not have to be melb or monash) achieve an wam of at least 80 in your 1st yr and transfer into the monash llb program (i was offered a place in monash's comm/law dbl following this pathway before ultimately deciding to do commerce at melb). Otherwise, achieve 99.90 in your vce and you are guaranteed a place in the jd progr once you finish a melb undergrad program - no lsats necessry ^_^.