If the money is not in your account for 4 months when you go to get the letter, you must sign a document giving them permission to freeze the funds for an additional 4 months. They will then issue the letter. Yes it's nationwide.

Must apply outside of Thailand through a Thai embassy.

You can't just choose any immigration office you want. You must use the immigration office where you live. If you live in Nonthaburi, then you must use the immigration office in Nonthaburi, and you must have proof of your address in that province.

There's no such thing as a non-O tourist visa. A non-O visa is a non-immigrant visa which has the possibility of letting you live in Thailand. A tourist visa is a tourist visa. You either apply for one or the other.

How long a visa application takes depends on the embassy you're applying at. They each process differently.

Only way is to leave without a re-entry permit which will cancel your extension. And then you would need to start over from scratch with a new 90 day non-O visa, and then applying for the 1-year extension afterwards.

Otherwise one way that you can't really plan is that if you apply for ab extension and your passport has less than a year of validity left, your extension will only run until your passport expiration date.

Should just be frozen until you're able to check in

Yes, that's how the Thai visas work. You must enter Thailand by 2 November. When you enter, you will receive a 90-day entry stamp based on your visa.

Generally, yes. There are problems shipping medications, and even shipping vitamins & supplements to Thailand. If they are stopped by customs, you won't be able to get them back without getting an import permit from the FDA, which is not going to be possible for most individuals.

@Arun ************

that's odd

@Rok *******

still easy to do yourself, especially if you just leave the money in your account all year.