The monument to Albert Wolson is south of Gettysburg on Hancock Avenue in Ziegler's Woods in front of Cyclorama. He was a drummer boy and did not see any action.
The last soldier that fought for the Union and saw action was James Albert Hard.
I will be adding more states once I go through them and make any corrections or updates. I have them all, so it won't take too long to do it. I also have a LOT of digital books on the war which includes rosters. You will find that a LOT of the states' units have "pictures" of rosters taken from these digital books. They are all in a PDF format of which a picture can be taken from any of the pages. I have done this which is saving me a LOT of time adding the rosters instead of typing each line.
I just added U.S. Colored Troops Medal of Honor winners 2/16/2019. There were 25 recipients.