DrJack54

Tax Identification Number. Explained fully here. https://www.siam-legal.com/Business-in-Thailand/tax-identification-number-thailand.php

Either way folk should not allow passport validity to be under 6 months if intend to travel. The issue would be with the airline. Ubonjoe makes some clear statements on the matter in this attached thread. https://aseannow.com/topic/1255340-passport-validity-when-entering/

There certainly has been a shift in regards to wanting full 12 month bank statements in lieu of bank book alone. That has been the case at CW. Couple of years back they didn't accept my bank book as there was 2 months zero transactions (I use dedicated bank account) Ever since I have supplied and recommended 12 month bank statement 200b. (saves the hassle) Good idea to get it day or two prior to application. Edit: For your extension did you supply TM47 and TM30

You mentioned FD account. The minimum deposit for most FD accounts is 1000b. Also normally a 12 month bank statement would not be required with a FD account. BankBook sufficient.

Additionally did you ask about your first 90 day report after return. Assume online will not be possible and you need to report in person.

In Feb OP had thread re obtaining 5 yr motorcycle license. The questions were covered. https://aseannow.com/topic/1350856-long-term-visa-needed-for-5-year-motorcycle-license/

One thing immigration is Red hot on is any dip below the 800/400k. Keep in mind that you are permitted to use two bank accounts. I obtained my most recent extension in Nov last year. My Thai partner does all the money stuff. I stated throw away line ..."that's another extension all done" She caused the balance to dip below 800k (by 1500b) Thought I would need start over. Then realized I had an account never used with approx 10k. Still means that I will require 2 bank statements and letters. PAIN. Some posters will say that immigration over looked a dip below. Can occur however rare.

Not sure what you mean by "arranged in one or two days" You obtain a COR where you are staying. You would need a TM30 in Bangkok (one example) in order to apply for COR. You can make an appointment for that so there isnt much waiting "hours" However a COR at CW will take a week to process. (They state up to 2 weeks). It is posted out 200b You would need 2. One for COR and one for bank account. The actual TDL is a quick process. Make an appointment and apart from the medical certificate you are right to go. Most transport offices have shop nearby that does the certificate. Plenty of information in TDL forum. You wont do all this in couple of days.

There are many threads on Aseannow that discuss LTR. Here is one example. https://aseannow.com/topic/1328779-ltr-visa-how-long-does-it-take-from-applying-to-decision/ That thread touches on use of an agent. That can be done for advice alone or more. I looked into it for myself however the option of income alone 80usd per annum was not suitable.

Offensive post removed

Get a DTV. Plenty of folks on annual extensions based on retirement. Monthly transfers of 65k

Not sure if there ever was one. The passport must have validity for period of stay. The airline at departure is another matter. In this attached link to thread with additional links. Suggest the OP renew pp. As pointed out by @HK MacPhooey taking day off work for pp renewal best option.. https://aseannow.com/topic/1328939-entering-thailand-with-a-passport-that-is-valid-for-less-than-6-months/

This is uncommon however other immigration offices have their "quirks" Jomtien as one example asks folk to return to immigration 90 days after extension to check financials. This is not really enforced. In any event we play along with the rules/games each office applies.

In another thread you mention that you currently have a DTV. Seems your issue is with the school. The child should be able to hop onto your DVT so to speak. Think you will find that what is pointed out in first post, regarding school requiring student to have a valid permission of stay in place in order to be enrolled.

Which immigration office?