The Civil War site you included does not indicate which soldiers died.
Here is information from the Civil War Pensions Index:
Charles C. Daniels, Co. H, 15th Regiment, Maine Infantry.
There is filing for a widow's pension only.The Date of Filing is 4 Oct 1862.The application number is 3586.The Certificate number is 3849.This would indicate that Charles C. Daniels died during the war.Unfortunately, his exact date of death was not entered on the index card, not unusual. I feel lucky when I find one that does have the date and location entered.