Questions about IIMBA NCKU

Yeah, I know what you mean. I found that the best way to get answers from them is to call them up. It shouldn't even cost you money if you use the Webtalk on http://www.imba.ncku.edu.tw/contactus/index.htm
You should note that what ever I reply here is not an official answer, and you should triple check everything.

Here we go...

As far as I know all international students have tuition waiver, free dorms and free 3 hours a week Chinese classes. This will probably not change.
The additional 3000-6000NT$ assistantship is subject to availability, though unless there are no other employment options for you - I suggest you skip it. The amount of work required for that assistantship is often not worth it.
There is an additional NCKU scholarship, depending on your grades and/or your research work, you can apply after a few months in NCKU. OIA issues the regulations and application forms every once in a while.
Each of those has nothing to do with the other.

Many of the south-east Asian nationals living in Tainan manage with that amount, though I'm not entirely sure how. Tainan is relatively a cheap place in Taiwan, and depending on your expected standard of living you can probably find anything from dirt cheap (lunchbox for 40NT$) to five-stars (3000NT$ meals). I would, however, suggest having some major backup funds. Some scholarships arrive late, especially at the beginning of the academic year when Ministry of Education is swamped with applications and paperwork takes forever in NCKU. Furthermore, most of the students I know in Tainan, most of them of the more western countries, tend to spend much more than 5000NT$ (scooter, nightlife, middle-class food, rent, etc.)

I'm not sure what A and B are.

I believe it's included but you should call up and check to make sure.

Good luck,
Fili