That's quite a pile of questions.
a) That's not always true. What I've seen is that generally you can ask the uni to credit those units as electives, which means they'll still count. Even if you don't do that, they will appear in your transcript as they will always be completed tertiary study.
b) That I can't answer. Maybe Lazarus or Minai can shed some light on it?
c) A
full academic load is the amount of credit points a normal full time student would be taking. A
full time load is not always the same thing: it is the amount of credit points required for you to be considered a full time student. This is usually 3/4 the number of credit points required for a full academic load.
At UTS a standard subject is worth 6 credit points. The full academic load for a semester is 24 credit points, whilst the minimum full time load is 18 credit points. Any less and you're a part time student.
At Macquarie a standard subject is worth 3 credit points. The full academic load for a semester is 12 credit points, but I don't have any confirmed information available about your minimum full time load. You should speak to the Registrar's Division or check your faculty handbook for this kind of technical arcana.
At USyd (just for interest) they have a weird (but logical, in its own way) system of increading credit load depending on the time when you'd be taking that subject. I haven't looked into their systemin detail, but it's quite interesting. Full academic load is also 24 credit points, again I don't know about the minimum full time load.
d) It depends on the university, faculty and course to which you are applying. UAC will consider all finalised tertiary study that ther receive notice of. However, certain courses have additional requirements regarding academic credit.