I didn't want to wait until May tax season to apply, so I got the Withholding and non-withholding form from my employer, then went to the tax office and paid the tax. After paying or settling the tax bill, you need to ask for blue page that is called the Individual Income Tax Statement that shows you earn more than 2x the minimum. They just need the last year.
2) employment letter
3) police criminal check
4) work permit
If you are in the country more then 183 days in the year, you don't need the health check or criminal background check from your home country. I'm not sure how you would qualify for an APRC if you were out of the country more than 183days?
I found that the people in all of the offices were I needed to get docs from were very helpful. At the same time, I did have to zig-zag a bit. The first review of my paperwork revealed I needed the blue tax form, so I got that. The second review revealed that my birthdate was incorrect on the police check, so I got that fixed. The immigration officer had mercy on me and processed my application and let me just drop the last form off. Being in Taiwan, I've learned that you just have to keep a good attitude and be persistent. That is not always easy to do.