I am Don's wife. Don asked for information in 2005. Not sure what you sent him then. Our son Matthew Iler (age 15) would love any information you have.
I have numerous letters (on company stationary) between Alonzo and Don's grandfather, originally Alonzo and then formally known as Don. This Don worked for the u.S. TREASURY. He lived in New York. Don II - my father in law was born in NY and lived in NJ most of his married life. My husband is Don III. My son is Don IV all have different full names.
The 1867 birth year & Georgia birthplace sounds right for Alonzo.
Not sure what else you need to verify. I have old photos, too. Not sure exactly who they are. My father-in-law was an only child.
If you respond I can give you my email to send directly or my hubby's email is still the same from 2005. Make sure to ask him to print for Matthew's school project.