A) Some questions may ask you to discuss textual form, and it is typically easier to compare and contrast the related text and the prescribed text in this case if they have varying textual form.
It is not essential, however it probably is better to have different text types.
Robert Menzies is a dry college so doesn’t allow alcohol on site and doesn’t really have the dreadful college culture that you get at other unis like USYD. Think Dunmore lang and the village are more party central if that is more your type of thing.
Syllabuses are available on BOSTES website so you can check you are covering everything. I would focus on doing the chapter reviews at the end of the chapter for textbooks to more quickly identify problematic areas.
It will affect your ATAR as all assessable tasks contribute towards your ATAR.
The best thing is to learn from what you’ve done in the past and improve on it.