@Mauricio *****
I'm not talking about "getting around the system". I'm saying the most efficient solution would be to let the half-Thai child to enter Thailand and go on overstay until you receive the child's Thai passport. Once the child has the Thai passport, bounce out with the child and have the child return on the Thai passport.
It's the most simplest, cost effect solution without any punishments or penalties .
1. Schools may not allow a child to enroll if they are currently on over stay.
2. The child's only 19 months old. The child won't go to school for another two years at the earliest.
3. It does not take two years to get a Thai passport (for a Thai citizen).
4. The bordering countries are reopening by air and should be completely reopen within two years.
Keep the process simple and cheap. Let the child go on overstay, and bounce out when the borders reopen by air with the child.
Don't make the process more complicated than what it is.