Just thinking about the missing members of Samuel and Catherine Hairs other children who died during the flu epidemic. I've located Clarence at Greenwood in New York. Clarence had a twin, Menzies. There was also Donald whom I have not yet been able to trace. It may not be easy to find the others without going to public records in New York in person. From what I understand, there were so many deaths in a very short period that bodies were buried in relatives graves without much ado or good record keeping, just to keep ahead of the disease. I don't know if that's true. Times have changed to be sure, but you still needed a death certificate to bury someone then as you do now.
Do you happen to know where Samuel is buried?