Official source states if a person has a tax liability, so if they don't, there's no reason to apply for a Tax ID. But you can if you want to. Many prefer to stay under the radar
Wrong. You only need a tax ID if you have assessable income. Unless you're working in Thailand or you come from a country which does not have a DTA with Thailand.
Properly? All I can see when someone says they can get you a 10,000 baht visa for 95,000 baht is SCAM in very big letters. But.......some people are ok with being scammed, I'm just not one of them