Some important changes for C3C version:
Field Artillery will have the "stealth attack" ability, as will the Confederate Irregular/Guerilla units. Coastal Guns and Fortress Guns also will be granted this ability. Howitzers will not due to the nature of their firing (higher trajectory).
A new unit for the Union, Freed Slave will be in. When captured, this unit will be converted to a Slave. When a slave is captured, it will be converted to a Freed Slave. These units will vary slightly in abilities.
Howitzers will be given the collateral damage ability.
Frigates, and Union/Confederate Advanced Ironclads will be given the collateral damage ability. Union Mortar Boats also will be granted this ability.
All Transports will require an Escort.
Confederate Cruisers, and Union/Confederate Sloops will be given the "stealth attack" ability.
Advanced Fortifications will grant a building which will make a city immune to "stealth attacks".
I plan on using all 7 "flavors" in the scenario. These will be Infantry Units, Naval Units, Artillery Units, Cavalry Units, Industrial, Scientific, and Structural. The Union will be flagged Industrial, while the Confederacy will be flagged Infantry Units. Each will have a varying relationship with the other types. This will basically "steer" the AI toward specific tech choices (Union more toward Industrial, Naval, Infantry, and Artillery in that order, Confederacy more toward Cavalry, Infantry, Structural, and Artillery in that order, both will be roughly average for Scientific)
There will be more additions and changes, but this is a good starting list.