I have dual passport Thai and Canadian. But my covid vaccine is under my husband last name. So, I have to travel back to Thailand under non 0 visa. That's how I can tell you from my experience. 🙂
I know you can buy extended Insurance even when you already in Thailand, I bought Insurance through the recommendation by Arawan Namak. I already asked her about this options before I buy. She will be able to help you with more information. She is very good.
I am leaving next week, No. 7 I used my Driver License in Vancouver. No 8 in your case may you try the copy of the rented condo agreement. For me, I put my family house registration. And I already got the visa, just wait for the COE, I hope this help