What are the visa application options for my child while I wait for my 1-year extension in Thailand?

Hello, I am looking for help in applying for a visa for my child. I just arrived to Thailand a couple of weeks ago, but am waiting to bring my daughter here until I have our visa situation settled, I have moved into our new house, etc. She is safe and sound with family until then, but I already miss her dearly and want her to come and join me sooner than later! So I would greatly appreciate any insight you have to offer.

I am currently being sponsored by an NGO in Thailand. I arrived at BKK and received a 30 day stamp, then went to Yangon and obtained a 90-day non-O visa. I just applied for my work permit yesterday, and then I intend to apply for a 1-year extension.

I spoke with an officer at the Kanchanaburi immigration office yesterday that was very unhelpful regarding my daughter's visa. Here is what I want to know:

1. The immigration officer tried to tell me that I would have to WAIT until my 1-year extension was granted BEFORE my daughter could come. And then they said this could take 3 months?! Is this accurate?

1. I am not sure yet if she will apply for the ED visa, or the non-O visa (she might go to a Thai school eventually, but for now we are thinking she will homeschool and take Thai language lessons before entering the Thai school system). Either way, it says that I will need a SIGNED copy of a court-ordered custody agreement as a sole parent. For better or worse, we never went to court, her father has just made an intentional choice not to be a part of her life. His name is NOT on the birth certificate. Is there anyway to get around needing a signed court order?

Thank you in advance so much for your help.