Meg refers to Lucifer as her father, but previously Azazel referred to Meg as his daughter.
There was an actual battle of Carthage, Missouri, which served as the capitol for the CSA in Missouri during the civil war. The town was burnt to the ground by Unionists but it was bloodless. There never was a massacre.
Dean is shown contacting Bobby from the store by CB radio since the cell towers are down. Bobby is at his house in Sioux Falls, South Dakota and Dean and the others are in Carthage, Missouri, which puts them about 500 miles apart. Even in ideal conditions (good weather, flat terrain) CB radios have a maximum range of about 20 miles, on average it's less than 10 miles. So there is no way Dean could have contacted someone that was over 500 miles away using CB radio.
In addition to the radio that Bobby used being a CB, they used an expired Amateur Radio Callsign which is not valid for CB radios.
Carthage is in Jasper county.