What are the Non-B visa application requirements for teachers returning to Thailand after working abroad?

Hi, I have a few questions regarding the Non-B application requirements for teachers. A bit of background info...I worked in Thailand for a number of years, with my last Non-B extension of stay expiring in March 2019. Since then, I have been working in Hong Kong. I have accepted a job at a new school in Thailand, which will start in September. I will most likely apply at either Penang, KL, or Singapore. I have a new criminal record check from my home country.

1. Will I also need a criminal record check from Thailand, since I worked there in the not so distant past?

2. Will I need a criminal record check from Hong Kong?

3. My home country check was notarized there. Does it also need to be authenticated by my embassy in Bangkok?

Thanks in advance.