correct for part 1, incorrect for part 2.
part 2 exemptions have changed effective from this year, you will now have to complete ACTL4001, ACTL4002 and the undergrad equivalent of ACTL5303.
entrance into ACTL4001 will require all part 1 exemptions, or, if one or two part 1 courses are missing, 70 avg across part 1 courses in addition to 3 months work exp. you will need a minimum 70 in 4001 to progress to 4002 (and presumably 5303)...
to gain part 2 exemptions, you will need a minimum 75 (equally weighted) average across the above 3 courses.
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anyway, the particulars aren't too important, its still a fair ways off for you guys, the important thing that should be made clear here is that part 2 exemptions can be gained in the 4th year of any degree that runs for at least 4 years, or through the masters program, or as a non-award course (for ppl who do straight comm)
in terms of the actuarial program at unsw, i'll be honest, even tho i am a unsw'er, macq's actuarial program is the more established one (though unsw is getting better, and more graduates from unsw are entering the actuarial workforce). if you are absolutely sure you want to do actuarial, then go to macq. but if you want to try it, go to unsw, it offers more flexibility (macq is only decent for actuarial, nothing else, other than ancient history).
one more note: if you are interested in combining actuarial with math (which usually is the common comm/sci combo for actuarial), unsw is most probably the best choice - unsw has a much stronger math department compared to macq. in addition, due to a special arrangement that the unsw school of math made with the ASB, you can actually double major in math and stats for the sci component of the comm/sci.
regarding differences between getting part 2s through masters, there isnt much, aside from the fact that masters may be more expensive (not sure about this), and also involves completion of several compulsory postgrad actuarial courses in addition to part 2s.