You have to do 90-day report in person at the immigration office that serves your address on your TM30.
If you count the days correctly, it'd be okay. As long as you go to CW and get the queue, you will served within the day. Totally up to you how and when you want to go for 90-day report.
You go to the Chaengwattana office at the Government Complex Building B for your 90-day report in person. Counter A for walk-ins, Counter B if you have an online appointment.
Right, you need a filled TM.47, TM.30 receipt, and your original passport.
There is no "minimum validity" rule when you apply for an extension. You can apply for an extension with a current and valid passport regardless of length of validity. You will get an extension until the earlier date of one year or passport validity. If your passport is expiring in less than one year, you will get an extension only until that day.
It might be able to apply for a Non-O dependent to a Thai Child with the right income and age if you are living together. Just your name being on birth certificate might not be enough. You may have to have parental rights to the child.
The age rule is a father/mother has to be 50 yo or over as a dependent.
Go to the local immigration office to get the detailed requirements.
In Bangkok, the 90-day reporting counters are at the Chaengwattana office (not at the IT Square Laksi Plaza office) counter A for walk-ins, and Counter B for those who have online bookings. (Except for people who are under BOI or on Non-LA)
Someone might be confused as Chaengwattana Government Complex is also in Lak Si district (means "Lak Si" words in its address).
, Taipei moved to eVisa system from this 1 January 2025. They don't accept walk-in/in person application any more. They state processing time is up to 15 days now.
Especially in Bangkok, you have to go to the Chaengwattana office for a yearly extension after the under-consideration period on the exact day they directed.