Anna Delm Aggregate points do not boost your atar from 95.75 to 99.75. Basically its the sum of your study scores that are ranked to give you your atar, you can check online for the tables its usually on the scaling report.
I dont know about unis but personally i'd go to unimelb mainly for the prestige and also cus i like the campus more so don't listen to me about uni preferences. and also latrobe is too far for me.