1. Yes, also on the Melbourne MD: first year second semester covers the physiology prerequisite. Second year first semester covers the biochemistry prerequisite. It's only missing
anatomy so you might have to find another way to satisfy that requirement.
http://www.medicine.unimelb.edu.au/docs/MDPrerequisitesVic.pdf(PAC1132 Systems physiology & PAC2151 Biochemistry and molecular biology are the ones in pharmacy)Also, there are other graduate schools for medicine without the subject prerequisites. I'm pretty sure only the UoM MD has the prereqs. If you're only looking at Victorian graduate medical schools, you should also consider Monash Gippy and Deakin. Plenty more interstate ones without prerequisites needed. Your pharmacology and therapeutics knowledge from pharmacy would help with graduate medicine in my opinion. Obviously you can drop the commerce component whenever you feel like. Hardly anyone goes through with it.
BPharm (4 years) -> pharmacy internship (1 year) -> pharmacist
BPharm (GAMSAT in 3rd or 4th year) -> pharmacy internship (GAMSAT again?) or grad med -> grad med or go work as a pharmacist and re-do GAMSATGAMSAT results are valid for 2 years. There are also graduate medical students out there who work as part time pharmacists during the holidays or when they feel like it (depends how flexible your employer is).
2. In addition to what vexx said, it's actually a bitch to maintain a high GPA in pharmacy. Do it and you'll see why.
5. Depends on your attitude towards it. If you hate pharmacy, it will hate you too. You'll get to know almost everyone in your year level by the end of the course if you attend uni, so yeah, pretty tight-knit course. I'd say it's pretty high-school-esque in a way. 4th years had hoodies and muck-up day. Loads of in-jokes within the course so there's entertainment value in it for you. Small campus, but you will find the solution to that is... INVADING THE UNIVERSITY OF MELBOURNE (just a few tram stops down). Academically, it's of the highest quality minus a few annoying lecturers. As you may know already, most of the admin stuff is done by someone else. I.e. allocate+, you don't ever do your own timetable - it's all automated. You will have 5 days a week of uni when practicals begin, with the earliest start being 8:30am (and you'll find that hardly anyone attends). Best thing about the course is having Lectopia for all your lectures, so you can ditch uni all you want and watch the lectures at home (you'll probably procrastinate and won't do it anyway). Did you ask anyone if pharmacy was their first choice? Most people had medicine first or won't admit it, you're definitely not alone.
EDIT: You're not allowed to overload during the teaching semesters. You're not even allowed to start the commerce component. Summer units may be possible but the problem is finding an anatomy unit from any other uni being offered during that time. I have a feeling the UoM CAP thing doesn't actually have any anatomy units accessible, you'd have to do some research (look into RMIT, LaTrobe, etc).