not trying to be tough, just merely trying to educate you on how to find answers to repeated questions instead of getting your knickers in a twist like you have here 👍
foreign income has always only been taxed in Thailand if you bring it in from overseas. That rule is in effect today. The proposed change is to tax Thai tax residents on their worldwide income irrespective of whether they bring it into Thailand or not.
whereas I've seen people in front of me at check in being made to buy either a return flight or a flight out of Thailand before being allowed to check in. As others have said, it depends on the check in person.
safe enough, just need to watch out for pick pockets. Only issue is PP is a bit of a dive. I would look into Da Nang more as someone else pointed out on here.