I might be a good idea to actually have the money in the bank if you are planning to continue living here, Thai authorities are obviously making it harder for people to circumvent the requirements
I brought my step daughter to Australia from Thailand and it was not a major drama, I did not need to legally adopt her. I married my wife in Australia before I brought our daughter to Australia.
I had the same issue with Kasikorn but the printout required had to show that the details that AIS held showed that my name, address and passport number all matched
The reason that authorities are cracking down on visas is because people are abusing the system. If you are not a tourist, i.e. your intention is to stay long term then you should apply for the appropriate visa.