Hello,
If you want to do Arts and Eco, you could do a Bachelor of COmmerce majoring in say Economics and Human Resources and and Bachelor of Arts majoring in something else..
Yes, it is 'ok' to start mid year with the Commerce/Eco program. Many people start in Sem 2.
In terms of the Applied Eco and Eco, there shouldnt be a lot of difference. I think they used the word applied to differentiate itself with the nearby ANU; but they are changing it back
In terms of the UAI, UC's minimum UAI goes up about 2-3 points every year. e.g. it went 70, 73 and 2004 it was 75. I would say it will go to 77-78.. But,, everycourse has different marks. I would put in an Arts degree as a preference and just pick subject you would be normally doing in the other degree and transfer in 6 months time and they will credit all the subjects...
Social life is really good, especially if you live on Campus. Yeh, very laid back. Everyone seems friendly etc which is good!