http://graduate.science.unimelb.edu.au/downloads/OD-prereqs.pdf These are the approved units that can be done outside of UoM.
The following is a summary of entry requirements to the OD. Applicants will require:
*An undergraduate degree (or equivalent); and
*A first, second or third year (or equivalent) subject in physics or optics; and
*A second or third year subject (or equivalent) in anatomy or cell biology; plus
*Two additional subjects at second or third year level (or equivalent) from one or more relevant biological science disciplines.
Yeah I was thinking about a BioChem major instead of the Genetics major considering I would already have done most of the required units. But genetics just seems fun to me D: More appealing than BioChem anyways.
The green highlighted ones are the UoM requisites. (I'm having seconds thoughts with it all D: Definitely will re-evaluate it after first year)
mmm haha i never really liked genetics. biochem would be more broad based sorta and it would have genetics in it and its useful for a lot of disciplines 
you could do something like this 
i dunno if you want to do human pathology which looks for anatomy type based (and i found that type of thing boring) 
u can still do genetics and immunology
but ur 1st year looks good, yep u could do the easy physics (and chem for that matter) pair phs1080 and phs1042... ^yep to a stats unit i did sci1020 (the easiest)
2nd year could be something like this 
1st sem
-dev2011
-imm2011
-gen2041
-bch2011 (u could do mol2011 if u want but i hated mol haha)
2nd sem
-gen2052
-sci2010
-phy2032 (just to mix it up) so u still have the prereq
-dev2022 (perhaps if u want to do the 48 point double major in imm, human path depending if u like that kind of thing)
and then 3rd if u want to do straight imm and genetics
1st sem
-gen3030
-gen3051
-imm3031
-imm3051 (or hup3011 in which case u must do mol2011)
2nd sem
-gen3040
-gen3062
-imm3042
-imm3062 (or hup3022 if u want to do human path)