Many of my friends are going, they are from miri, so get to look out for them. =) I supposedly to go, but i'm off to perth now.

You will be learning in a university-type environment. For each subject, you'll have 1 lecture and 1 tutorial a week. A tutorial is a smaller group(about 14 students) which enforces what you learn in lectures. Thus, there would be no need for private tuition classes.
You could probably take accounting as a 4th elective. It is quite easy to score and it could help you.

The prerequisite for dentistry is(assuming you take chem, maths 1, bio and accounting):
Subject 1: English
Subject 2: Chemistry
Subject 3: Maths 1, Maths 2 or physics
Subject 4: One other-Biology, Accounting, HOI

Thus, using this combination, you could easily use accounting as your best 4 just in case your bio mark is not very good.
Yup, you are allowed 5 subjects, but some students take up to 6 subjects and get 7 marks in their result slips(including EAP). Since you are not taking any science subject, you will have quite a lot of free periods. So, I guess you will be better off doing another elective. You could always drop one subject after term 1 or 2 if you think you can't cope.

Good luck guys!

You will have 2 free periods every week if you are taking that combination. You have chem and maths 1 optional extra classes on Saturdays. I recommend that you go for the chemistry class. You also have optional bio and accounting classes, but I'm not sure when since I did not take those subjects.