Immigration rarely ask for evidence of your return flight but airlines often do. If you haven’t got a flight out of Thailand within the first 60 days, they may refuse to let you board. It may also cause issues with your travel insurance.
The 30 day extension you get the same way you have always done.
Yes, I can imagine. They are often quite small establishments. I’ve been staying in the provinces for ten years. Very happy to say it hasn’t been an issue for me. Yet.