It’s difficult to work in Thailand and stay longterm unless you’re 50 years old or older. Lots of information on the Thai Embassy website for your country and on Google. When you are serious about starting a company or buying into one, legal advice is definitely recommended. Everyone talks about how nice the Thai people are and they are in general. However, there are also Thais that take advantage of foreigners. You need to protect yourself from them.
I had kind of the opposite happen to me when I landed at Phuket Airport 2 days ago. I came in visa-exempt but made the mistake of telling the Passport Control agent I was visiting my wife instead of just saying I was on vacation. She asked me why I didn’t have a Non Immigrant O visa. I told her I would have to pay for that and don’t have to pay for visa-exempt. She called her supervisor over, they chatted for a minute, then she stamped me in for 60 days. I was seriously concerned before then.
Two years ago, when I got married on Phuket, I needed a certified copy of my birth certificate and a certified copy of my dissolution of marriage to my first wife. Both may have been needed by the US Embassy in Bangkok in order to give me their clearance to marry. I think I needed two certified copies of each.