No one who was a witness to the Battle of Gettysburg would doubt either the honor or the valor of the Army of Northern Virgina. The Confederate infantry who fought there belong to the Ages.
The infantry are the soldiers of an army which travel and fight on foot.
I appears not. The 13th Ohio Volunteers seems to have been engaged further south in the areas of Tennesee, Mississippi and Georgia.
Infantry is the army, the men who fight, and who march into war. They are the "boots on the ground" and the men who fight battles on the ground.
The Battle of Gettysburg happened in Pennsylvania.
They were civilians trained to fight in emergencies
While not entirely accurate, this approximates the way the battle of Gettysburg began. Gettysburg was selected as a location for the fight by Robert E Lee because of the excellent road network there. Lee's soldiers had raided many of the nearby towns and hoped to force Gettysburg to give them a warehouse full of shoes and boots. They were surprised by the presence of a Union cavalry company when they had only expected a few untrained militia. They did not know that nearly 100,000 Union soldiers were within one day of arriving at the scene.
A couple of men who were militias were told to fight in the Revolutionary War. In the US, the militia is entirely voluntary.
Pilots fight in the sky; Infantrymen fight on the ground.
No, they were not a state then.