What are the requirements and process for transitioning from a Non-B visa to a Non-O visa for marriage in Thailand?

Hello everyone, I am on Non B based on yearly extension that is going to expire mid Nov 2020. I have to change from Non B extension to Non O extension based on marriage to a Thai National with a kid. I assume the following will fullfil all the requirements.

1. 400000 baht seasoned for two months before apply for extension

2. Passport with valid visa stamp

3. Marriage certificate set

4. Child birth certificate

5. House registration of wife /rent contract

6. Photos at our residence inside and outside

7. ID card of wife

Is there anything missing out pls guide. Any one in the same situation?

I am thinking to apply 3 weeks before the expiry of extension like 20 Oct. Is the time enough to switch visa from Non B to Non O.

Thank you in advance