Hospital stay at your cost. Check with your insurance company if they will cover said stay. Most will not if you found to be asymptomatic and/or made to quarantine on your hotel rather than hospital. The latter will not be covered.
Yes...but you will not be able to get to the front of the line, so to speak. It is Thais first. Also depends upon vaccine availability and length of time from when you received your second jab. As a side note: check the US Embassy website as there are jabs being offered in CM and BKK hospitals and other locations now.