Some embassies indicate the financial evidence they want to see but most just want to see they can pay the course fees and living costs. You don't say how old your daughter is but if she's under 20 then a sponsorship letter from saying you will cover all costs should suffice

Your problem is that you used an agent for your existing extension so you won't have met the terms of that extension. Even if you had 800k baht in the bank its very unlikely you could do the next extension yourself. You are stuck on the agent wheel, you will have to continue to use an agent for the foreseeable future. The only way to get off the agent wheel is to leave Thailand close to the end of your current extension (without a re-entry permit) and either apply for a 90 day Non-O visa in another country or come back in visa exempt and apply for a 90 day Non-O visa at your local immigration office (by meeting their requirements) and then applying for a 12 month extension (they may or may not allow you to use monthly income at that point, but chances are they won't)

Yes you can receive the email over the weekend but you have not been waiting so long. Better to relax and enjoy your time there

I can only imagine you have provided some bad information but I've no idea what

@Graham *****

for an extension of stay based on marriage it has to be in the bank 2 months before applying

You do need to ensure that you have 12 full months of a minimum of 65k each and every month at the time you apply for your next extension, not the date your extension is due.

@Thomas ******

not every office can do an in country Non-O visa, I don't know about that office. The other requirement is you have at least 15 days left on your current stamp (21 days in some places) but this shouldn't apply to you as you've not long entered.

@Sovann ****************

there's no chance that even a treatment plan will work if it only consists of 2 hospital visits. You're going to need multiple visits over a period of more than 6 months

@Jorge ***

there is no requirement to get an extension. But its not going to take the embassy long to work out what you are doing and I'd be surprised if they would continue this indefinitely. It used to be possible to get a 12 months multiple entry Non-O but this stopped when they moved to online.

@Jen **

normally with a joint account you need double the money in it