David is correct. If the loan is made, then no adverse action notice is required. Although, it is very easy in a wholesale shop for these unwritten counteroffers to become forgotten. The applicant does not accept the counteroffer and the file is found four months later with no adverse action letter or counteroffer letter in the file. And, now you are in violation of ECOA. I used to see this every day in the wholesale shop I worked in. It is not any fun to have to go through several hundred (yes, I said several hundred)files that have just been sitting for months with no final action taken.
One thing I have never understood is that the counteroffer details have to be communicated to the broker. Why not just go ahead and issue an adverse action/counteroffer letter to the broker? If the loan never closes, you are still in compliance.