Germany would most likely still not have won without the help of the USA, but they certainly would have had a better chance. The surrender of Russia left a power vacume that shifted the balance of the war, and the United States shifted it back in the favor of the allies. With the threat of Russia on the eastern front gone, and a weakened western front without the aid of the USA, things could have turned out very differently.
Now, on the other hand, the CSA, being almost completely unindustrialized at the time of the civil war, would not have survived as a state for more than a decade on its own. To think that they still would have been around by the time of world war 1 is ridiculous. The CSA and USA would have most likely, having lived for a few years apart from each other, realized that they had more to gain being together than separate, and reunited.