Firewater's origin is hinted at in the story and we do get some background on The Wilde in this issue as well. Ultro's origin is covered in Argo 5 #26. An origin story for All-American is in the works. I don't really do handbook pages preferring for each character's stories to unfold. I did do Kasira, Blue Dynamo, Shazrath, and Gladiatra's origins in Argo 5 2, 6, 18 and 26 respectively but Team North America have had less appearances.