For me, PROBLEM SOLVED
After spending a week or so tearing my hair out trying to figure out a way to open an American bank account from Thailand, it turns out that you can indeed have direct deposits go into Transferwise, with standard ACH rather than IAT format. I did not understand that until Transferwise sent me an Email telling me how to do it with use of a "borderless account" right on their own web site.
Once you have set up a Transferwise account and provided a bank name and account number into which you want Transferwise to send your money (in my case that is my Bangkok Bank account in Thailand):
TransferWise wrote:First after you log in to your TransferWise profile go to the Balances section on the left hand side of your profile – You will see a button that says Get Started – You can then activate the USD currency to open the borderless account.
You will then get your USD bank details when looking at the Balances area of your profile.
Of course many more currencies other than USD are available.
There will be a currency logo at the top of the page. You click on that logo and a page pops up showing your name, a Transferwise account number, routing numbers for both wire transfer and ACH, and their New York address.
Again, they'll have an address for your home country if you are not using Transferwise from the USA.
That's the information needed for direct deposits. Once it is getting close to April 1, I will cancel out the direct deposit that goes to Bangkok Bank's New York branch and instead have my direct deposit go to the Transferwise account. That will eliminate the need for the IAT format.
Transferwise's fees to then transfer the money into my Bangkok Bank account are more expensive than direct deposits to Bangkok Bank's New York branch, but for me it will be well worth it to eliminate the need for paper checks being sent to me and then having to wait 45 days for them to clear after depositing them into my Bangkok Bank account.
Definitely a big relief to discover the entire process was available via Transferwise all along and I simply did not understand that. Well, I sure understand it now . . .
I thank 2lz2p for telling us about the existence of Transferwise.