What are the reporting requirements and financial proofs for a Non-O visa holder in Thailand?

They don't even consider shortage of one day!

Maybe do your research on the government site and don't rely on Facebook bullshit.

It would be helpful to mention what visa you arrived in Thailand on? You mentioned your first report, are you eluding to the 90 day report? In future just try and give as much detail as possible that way you will get some sensible answers to your questions.

You can go 2 weeks early or 1 week late for the reporting. Go the day you have had the cash in for one month

Get a visa service

If you are on a 90 day Non-O visa you don't do a 90 day report until 90 days after you get the 12 month extension, normally they'll put a slip of paper into your passport with that date.

But I'm assuming you want a 12 month extension of stay and for that the 800k baht must be in your Thai bank account for 2 full calendar months before you apply for the extension. That means your extension will most likely be refused. The simplest way forward is to visit a nearby country, apply for a new 90 day visa using the evisa system and remain there until it is issued. Return to Thailand and apply for a 12 month extension when you have 30 days or less left on your 90 day visa and be happy you already have the money in the bank

First time apply, 2months in Thai bank,second time 3months in thai bank, and you need to apply 4 weeks before the end of the o-visa ends to give you time to get it all together

No

Since when is it necessary to have the money ONE month in the bank?

Isn’t it 3 (resp 2) months?

What Visa are you on or, more likely if you are doing a 90 day report, Extension of Stay based on what? There is no financial requirement for 90 day reporting and no 90 day reporting if you are on a Non-O Visa so which is it?

I don't understand your question. If you entered visa-exempt and want to apply for the "change of visa type" to a 90-days Non-Imm-O Retirement Visa, all you need to prove is that the 800,000 THB are sitting in your Thai bank account. Only for the follow up application to the "1-year Extension of Stay Permit", you need proof that the money has seasoned for two months. . . . you need to do the 90-days report 90 days from the day of your entry. You can do it from up to 15 days before the due date, and up to 7 days after due date

Report due approx 31st April......90 days from when entered country due report

Report is just to say u haven't left country. 800k doesn't affect that. The 800k is a long term visa requirement.