As to Wayman Holliday - his service record indicates that he survived the war. He appears to have been around 18 (YOB about 1844) when he enrolled on March 22, 1862 at Wellsville (Guitar's Mounted Rifles, CO D which became the 9th MSM Cav, CO D). He was mustered in on April 19, 1862 and mustered out on April 21, 1865. The only notable item was his horse died from exertion chasing bushwhackers on August 9, 1863. (The Company Event Records for July/Aug 1863 only state that they were stationed at Germantown, MO). He filed for an Invalid Pension in 1892 and his wife filed for a Widow's pension in 1894.
There was a Wayman Holliday that was paid by the City of Wellsville in 1892 for services or merchandise for the police department. He was born around 1847 according to the 1880 census (and was a teamster at the time).
I know this doesn't answer your real question about the 9 UNKNOWNS, but Holliday can be marked off the list as dying during the war.
Craig