Just a word on Thai probate based on my experience in 2011. I am not a Thai citizen.
My Thai wife died suddenly and had no will.
I went to the local court (Taling Chan branch in Bangkok) to see what the procedure would be to become the "administrator of my wife's estate".
The staff were very helpful and professional. I just needed to obtain the signed release from our two adult children (who would be the first in line for the 'administrator' role).
I just provided the death certificate, copies of some of my wife's major assets (e.g., land deed, car, bank account), marriage certificate, and my passport info.
Then, several weeks later I appeared in court. The judges asked me a few questions, and that was that. It took 5 minutes.
I did not use the services of a lawyer. I don't think there was any cost, other than photocopying.
I used the court order to have my name added to the land deed (which, in theory, allows me to sell the land -- but not the house which sits on it. But that is another story.)
The transfer of ownership of my wife's car and bank accounts to me was straightforward and quick.
Have some faith in Thai institutions for a change.