I admitted those 2 states are mostly due to rule of cool. But the Confederacy didn't end up as French ally very long as they had their own design for Mexico. The British was their main business partner though. Well, it had already been a generation after the war, the grudge was fading. And the US joined WWI on the Entente's side very late, mostly because of Japan. Japan received a telegram from Germany which asked for them to open a 2nd front against Russia. The Japanese accepted, and while marching into Fengtian, managed to set up a puppet state with Puyi as emperor. Fearing its access to China being cut off, the US declared war and engaged Japan in the Pacific.