If you are a DM, you probably have lots of miles to burn. I would definitely do it in business and you should be able to find low inventory for 120k miles per person.

You'll run into blackout dates on KE, so that airline is out. MU has availability to BKK via LAX on 12/20, however getting ATL-LAX on DL will be tougher.

You should also be able to route through LGA, EWR, or JFK on DL then do MU to BKK via PVG. It'll be easier to find ATL-NYC, but might be tougher finding NYC-BKK. I'm seeing availability on 12/19 and 12/23.

Getting back home is going to be tougher in business. I didn't spend a lot of time looking, but wasn't seeing good MU availability anywhere.