I own 2 companies for 11 years and employ 47 staff. And still I have no full understanding of all labour laws. Talk to your accountant and get educated. Maybe you should get off your high horse. Good evening.
Yes. You can take the stairs or elevator inside the transitzone and go fron departures to arrivals freely. All this area is before the border or immigration.
You don't need to stamp into another country. You can stay in transit and fly back with the same airplane. BUT! make sure you keep both bording passes to show Immigration in Bangkok. I'm not the only one and you can find numerous accounts on this page of people who did this.
Each and every Amphur seems to require a different set of documents. Apparently I live in a very easy going Amphur (Sansai, Chiang Mai) all I needed was my PP holding a valid visa, Cert. Of Res., my gorgeous facepics and a document filled out by my partner who holds the blue book. That's it. Done in 2 days.