My condolences. I am not sure if there is a specific list for Thailand. My daughter brought my sons ashes to Thailand to be interred with me when I go. All she had was the death certificate, the crematorium certificate and a note from the Undertaker. She wrapped the urn in a towel in her hold baggage. On arrival at BKK she went through customs and showed them and they just said OK. The airline didn’t query anything on checking either.
If you want a non o based on marriage I believe you must apply initially in your home country. Then you can extend it here as long as you have the funds etc.
Depends on your age. I had that once. I said go ahead and they went through all the opening paperwork etc and at the last screen it told them I was too old for their insurance!!! Still got the account though 555