Correct me if I'm wrong but these sound like Forward bases or mini-TCs that you can hide in order to collect resources.
Ive lived in Georgia and Texas my entire life and my uncle is something of a redneck/professor of American history, so I know a couple things about southern history.
The Confederates could be a pure military forward base with CDB type settlers but with a slower gather rate, and instead of the colony being a saloon it could be a remodeled blockhouse or warhut.
Their unit could be something like a sniper(which the confederates were well known for) with a very long range but low attack and hitpoints (they had lots of inexperienced snipers that were there purely for psychological warfare).
Their calvary could be a anti-infantry, dragoon with high attack but short range and low hitpoints. a good name (if there is such a thing for this unit) would be "Black Horse Cavalry"(famous Virgina calvary) or just about any thing generic would fit.
I know very little about balance, and less about modding. but if you care about historic context then these models(maybe not the stats) would fit.
If I think of anything else ill speak up
"If at first you don't succeed , try, try again. Then quit. No use being a damn fool over it."
-My dad