My flight arrives in Bkk at Suvarnabhumi airport at 2:30 A.M is there a 24hour money exchange there?

Yes, but why not just use the many ATMs there and everywhere over Thailand. Put in your card and out comes THB. In the airport, buy something to get change from the 1000s that you usually get from money changers and ATMs. You will need smaller bills, like 20s now and later, too.

Most on-line bank sites, that you use secret password to get into, have an item to click saying "foreign travel" so click that and fill in your travel dates and destinations. In case that is not done, travel with a real credit card too because they are closed less fast than bank cards if foreign use is noticed.

The plural of Baht is Baht and the plural of Thai people is Thai.

I went there and had no problem with exchanging. At the airport you can exchange cash for Baht so maybe bring cash with you and keep it safe on the flight. I arrived at like 11 or 12 at night so hopefully it's still open at night.

Consider it a blessing your bank doesn't handle baht. You would get a horrible rate guaranteed. ATMs best choice as mentioned above.