Coherent, well-argued writing with emphasis on citing your sources is important. Some departments have formal rules about how a paper should be written and handed in. You will be given many chances to write while studying in Australia. This applies to final examinations as well as to assignments during the semester. It is very unusual for professors to give a multiple-choice examination in Australia.
Essays are the rule, even in technical fields and social sciences.
The tradition in Australia is to attend university close to home, so the vast majority of students live in apartments or rooms in town or at home. So-called residential colleges grew up to accommodate students from further away, but these are separate institutions and are not run by the university itself. While many colleges are actually located on the university campus, others are adjacent or nearby. When you apply to an Australian residential college, you submit a separate application from your university application. Therefore, it is entirely possible that you may not get a place in college.