Things like this hardly ever seem to go just right, however this is bad. I'm putting this on my local messageboard since we have some people in Biloxi and a local car tuner in Mobile. Maybe someone knows this guy....
I bought my 67 Mustang in Detroit (1200 miles). Had the money wired from my bank to him when I was standing next to him at the bank, but there was a problem with it taking 24 hours to register in the account. So I had to stay in Detroit an extra night.
About the tags.... all states I know of offer a temp permit at the license office. Though he would have to have the title from the bank and signed over to you when you arrive. This whole situation is a mess, and I just know my wife would be tearing into me about it.
Hope it works out for ya!