Departure is not required. Don't even touch it and leave it blank. If you touch it, then all the fields become required.

@Det ******

I'm assuming that's a language thing and it's actually the certificate of single status to say you're not already married

A Thai embassy in a foreign country issues this document. It's not needed in Thailand as the law in Thailand says a 20 year old is an adult.

It's been down for months

There's no checks on your insurance for LTR. And no one has applied for the second 5 years yet so no one knows how that will go.

@Peter *********

the only way to get that stamp is to have a re-entry permit

The only official in Phuket that can sign the residence certificates is at Phuket Town. That's why the price there is 500 baht and you can get it back same day. For Blue Tree, you're paying an extra 500 baht because they have to drive the paperwork to Phuket Town, and that's also why you have to wait to get it the next day.

20,000 baht is the amount of cash a tourist can be required to show to enter Thailand. It's not relevant to a marriage visa at all.

To get the marriage visa from your embassy, you need to check what their requirements are. It will be a local equivalent to 400,000 baht in your local currency. Generally the only requirement is that you can show a bank statement (in your name only) with the amount of money. Some embassies MIGHT accept a joint bank account, but you would need to show double the required amount since only 50% of the money is yours. An IRA account would not qualify.

There is no updating a TM30. A property owner can file a TM30. Once filed it cannot be changed. Only a new one can be filed.

Nothing fancy. Just stating you're an employee, for how long, you can work remotely, etc.