Napalm? Claymores could be devilishly effective against a union charge too. And smoke definitely has its uses(shield your troops from yankee cannon fire. Damnyankees)
The smoke would be great, and doesn't feel like cheating too much, like some of these folks want with "Puff The Magic Dragon!" or "Fuel-Air Bomb!".
Yes, but as I say, the south simply did not have the industrial capability to produce spare parts, or whole guns, even if they had been given them. Its the same reason they never could really copy the spencer or henry rifles. Try as they might, they couldn't produce high quality ones fast enough to meet even close to the numbers the union troops were getting. Now, asking them to make spareparts/whole guns for a type from 100 years in the future...no way.
But there is clearly nothing the least bit tricky about smoke. Hell, I could design something for southern production. Simply take a congreve rocket, increase the warhead drastically so that it flies for only a very short distance, fill the warhead with a smoke making material (slow burning gunpowder? maybe even have it be one bi rocket that shoots out smoke for its entire burn, but lands a long time before it burns out), and put it on an easy to set up rack behind your front lines. Voila! Smokescreen, protects you from all that nasty arty and gives you cover for a bayonet charge, if you please.
I doubt smoke would change much on the battlefield. Any reports already state the just from normal musketry, the smoke accumulated to the point at which it was a peasoup that you could barely see 10, 15 feet in front of you. Adding in launchable smoke rockets would hardly change the conditions.
Excellent point: with all that black powder they already had smoke!
But if the rockets hit near the position of enemy artillery, then you would be immune from long range fire until they repositioned their guns. If you use a long burning, smokey motor and no warhead, then you could achieve long range, enough to hit enemy artillery if launched en masse. Since the rocket has such a long burn time, it keeps spouting smoke after it has landed.
Those guns could easily be pushed by hand through the smoke. Plus, with all the smoke created by the gun firing themselves, half the time they were basically shooting blind.
...well fine, fill the engine with caltrops or something then.
I didn't make it!
Barring that, radios. Communication is far more important than the weapons themselves. If units can instantly transmit data all over the battlefield you wouldn't see most of the routs that really lose a battle for you. Plus I'd bring back the blueprint for a bolt action rifle of some kind. Would be easy enough to manufacture for the South, but still provide far greater range and faster firing rate over muzzle loading rifles.