The guy doesn't speak with an Australian accent.
No. Though to be honest, other than that he's not a terrible Heath, if you can say that about a guy who really doesn't look or sound at all like Heath playing Heath. Still, there's some kind of faint similarity there.
Is the older guy supposed to be Jack Nicholson? No similarity there whatsoever, but I thought I heard "Heath" call him "Jack," and then there was a sort of lecture on drugs and lifestyle.
It's like this is the filmed version of that Esquire piece.