the obvious answer that everyone knows the answer to is he needs to go to the immigration office in the province where he’s gonna live. Issan doesn’t mean anything it’s just a general region of Thailand as everybody knows except maybe the OP
correct you can’t be working for US company and get the foreign tax credit just because you’re living  and working remote in a foreign country of your choice.
wow I live in Phichit province, and the immigration officer told me personally that as long as I didn’t leave the country, but came back to our house didn’t have to re-file
I don’t know for sure because I always transfer my money to Bangkok bank in New York and then they transferred to my local branch in Thailand. I would assume it does show as an out of country transfer because that category has not always been available. But I would check with Wise to be sureor you can transfer a small amount through Wise to your Thailand bank and see how it shows up.
I can go along with that, but I wouldn’t consider buying health insurance a financial matter. so why go to a financial advisor. For insurance I would go to someone whose sole purpose in life is to sell insurance and advise people on insurance costs and comparisons.
maybe she meant the document had to be certified from the Ministry of foreign affairs, I know every time I have gotten anything from the US Embassy or consulate. I had to send it to the Ministry of foreign affairs to get their stamp.