One other Earth 2 thought. In their USA, slavery never happened. Segregation and racism did. In their present day, segregation & racism have been over for a century before their WWII happened. Still, Hitler and the Holocaust still happened. The events of WWII can be shuffled to more recent times as long as the events and horrors are the same. I'd also have their tech be slightly different than ours ala Earth 2 on Fringe. Blimps are still in common usage. Clothing there is a little more vintage flavored, but it it is still 2019.
Come to think of it, I'd say Animal Man & his family either moved to Earth 2 or were always there. Our Earth keeps Vixen, and she's on the JL alongside Diana, Dinah, & Shayera. Earth 2? That's right: Earth 2 is Carter and Shiera, our Earth is Katar & Shayera. Each pair is a married couple. Carter & Shiera have two kids: Hector & Kendra. Kendra is married, & her last name is now Saunders.