Can't offer too much advice about Aussie requirements, but some pretty global ones include having passed the year 11 school exams for math, English, and a science (physics is good; it's actually pertinent), and the ability to hold a medical.
Does the scratch on the cornea affect your vision at all?
I'd imagine that if you were accepted, passed the training etc, that it would be a case of "go where you are sent", with no guarantee of a placement in QLD. (I hear they are rather short in MEL centre...)
You may find it worthwhile to x-post this on the D&G General aviation sub forum, also.