, was your original visa valid for 90 days (Non-O), not 1 year (Non-OA)? what is the letter on visa-class (Non-O or Non-OA) on your entry stamp when you entered on that visa?
If it's Non-O (original visa was valid for 90 days, single entry), you are not required to have insurance for next application for 1-year extension based on retirement.
, there are some conditions for monthly income method for retirement extensions. Please make your own post for further detail as this is post about an extension based on marriage to a Thai.
, right. But sadly, not all offices accept monthly income/transfers to a bank account method for an extension based on marriage to a Thai unless you are working inside Thailand legally with a work permit.
As a rule, you don't have to have 400K baht in your Thai Bank account for the whole year for a 1-year extension based on being married to a Thai national. You only need to have your funds for at least two months as of application day for the next 1-year extension.
BUT you should check with your local immigration office for their detailed requirements as some province offices MIGHT require you to have the funds for a longer period.
If you are going to the local immigration office for 90-day report in person, the reporting window is from 15 days before until 7 days after the due date.
If you want to try to do it online, reporting window is from 15 days before until 7 days before the due date.
, documents you have to submit are different depending on the reason for your Non-O visa (retirement, marriage to a Thai, guardian, trailing spouse, etc). Please make your own post mentioning what your Non-O is based on.