you don't need to think about a student visa yet until you have a firm offer from a school and have paid the deposit, at which point they will give you a confirmation of enrolment (CoE) code. this CoE is the number you need to apply for a student visa, and you can't without one. at that point it's a question of going on the web page for DIMIA (
www.immi.gov.au) and downloading their student visa application. i'm not sure what the policy is right now, but when i came to Oz to study abroad i didn't have to undergo any health checks, but then when i enrolled as a full-time student i had to get a chest x-ray and TB skin test and send the results with the appropriate form for a student visa. (for some reason i guess they think 4-month study abroad is not enough to infect the country with TB. who knows. whatever.) but, like i said, you do not need to worry about any of this until you've gotten your offer from a school.
as far as your GPA, you won't be able to translate it to ACER standards in the application form. just ignore that part; they'll do it for you. i mean, duh, go ahead and estimate it for yourself but they won't ask for that from your paperwork.
MCAT--i'm not sure, i didn't use MCAT, i did GAMSAT, so it was a question of quoting my candidate number to ACER. but i THINK (someone confirm or deny this--i know it was true for u melbourne but i don't know about the others--this might have been since melbourne GEMP starts in semester 2/july rather than february) that you can apply with a "pending" August MCAT. i'm not sure about that though. but when i applied to melbourne through ACER, they hung onto my application for months because i was international and they had to wait until all the international scores came in, particularly from August MCAT-ers. (it really ticked me off too, because that meant if i didn't qualify and they were supposed to pass my application onto my second choice of ANU, i would have missed the deadline for ANU!) since it sounds like you have your scores in hand anyway, i guess you just request that ACER be sent the official results?
transcripts--get the official sealed deal from your undergraduates and post those in the same package as your application to ACER.
and as far as the limit on application, yeah, it's not like the US undergrad or grad system where you can apply to as many schools as you want. you pick your top choices (or the top two you expect you can get into) and list those on the application to ACER, and ACER sends your application to your top choice school. then if that school doesn't like you, they will pass you on to the second choice school. the exception to this is schools that have an additional direct application for internationals--sydney did when i applied, so i used that as well as ACER. (what i did was make a general app to ACER listing melbourne and ANU, and a direct app to sydney.) choose your school carefully, because you only get to choose once and won't have the luxury of more than one acceptance. (unless you do direct apps to schools that allow that.)
riiiiiight. have i covered everything, now that i've rambled long and hard and procrastinated my thesis some more?
back to the jellyfish!