, if using the deposit method at the Embassy, the money needs to be on account 2-3 months before applying for the Non-OA. Check details with Embassy. When you have got the visa, the Embassy wishes you a safe flight and leaves you be until next time.
, yes. So in the worst case, you will have to return to your home country every second year to get a new Non-OA. For many ppl this is a more easy way forward than getting 800k on account in Thailand or proving 65k every month in Thailand. Most Thai embassies will accept the annual tax report as proof of income.
, therefore in a lot of cases a better idea to apply for a Non-OA at the Thai Embassy in your home country as they are (normally) much more flexible on how to prove funds of either 800,000 THB on account or income of 65,000 THB NET per month.
The basic problem is the fact that there is no official source for this. Even though you might find it on the MFA website or the Immigration Bureau website, it is not the same as this is the authorized source implemented everywhere or even commonly implemented. You must ask FB groups like this who collect a lot of reports from people entering Thailand. This way you will get to know what is the commonly established practice, but still open to the idea of the "Immigration Officer of the day"...
, not necessarily Thai health insurance but health insurance complying with similar requirements. Thai health insurance might be a cheap solution. You can look up the requirements on the Embassy home page.
Should not be any issue. Most Immigrations are not that restrictive on the 24-hour rule, and no one will ask you to do something not possible because of weekend or public holidays.
The Non-OA visa is an option used by many as their first retirement visa even though you will need health insurance for this of one year. The Non-OA gives you 1 year per entry and is much more flexible on how to show financial proof as getting it at the embassy in your home country. It gives you plenty of time to get a bank account in Thailand for the longer run.