What is the easiest uni to get into undergraduate medicine in Australia, in regards to ATAR?
There's no such thing as the 'easiest' university to get into as demand for medicine places is quite high no matter which uni you choose.
However, since most unis look at your atar + umat + interview, if you score highly on the Umat and slightly lower on your atar and vice versa you can still get in.
I'd assume bond uni has lower requirements for medicine compared to other universities (as they only offer full fee places). James cook university looks at only your atar and interview, but you'd still need a 98+ or more to be competitive. Special considerations such as SEAS can also make it easier.
If you really want an idea of what type of scores will get you into what unis I'd recommend you go to medstudentsonline and look at their offer threads.