Had no idea this thread existed!
Having indexed the first 60 issues and four Annuals, maybe I can give you a little perspective, shax:
1. Timelines. Forget about the series taking place in real time. The Howlers participate in a number of real-life military operations over the course of the series but these are presented all out of historical order while Our Heroes' continuity proceeds linearly (with the exception of the four Annuals). As for the D-Day sequence at the beginning of #1, you should simply ignore it. After all, it shows Junior storming the beach with the others... and he was long dead by 6/6/44.
2. The Howlers. You might want to go back and re-read #1 more carefully, particularly the captions on pages 2 and 3. I don't have it in front of me but I'm pretty sure there are more clues to the team's backgrounds than you caught, including Junior's Ivy League background, Dino's Hollywood career (it isn't that he's a master of disguise, incidentally, merely the only Howler fluent in both German and Italian) and a reference to Izzy seeking revenge on the Nazis for their treatment of "his relatives." Also, I'm pretty sure I read that Gabe's being white in large parts of the first three issues was the result of some executive (probably not Martin Goodman) fearing the book wouldn't get distributed in the South if a black man was shown fighting alongside and being treated as an equal by whites. Don't quote me on that, though, as I could be misremembering.
3. Tone. I've long maintained that some of the brilliance of those first seven issues derives from the difference in the two creators' military backgrounds: Kirby was an infantryman who fought his way across Western Europe and knew the realities of combat while Stan served stateside with the Signal Corps. I suspect Jack made Sgt. Fury so ludicrously over-the-top as a parody of the entire genre and especially of the endless stream of movies and TV shows issued in the two decades following V-J Day that glamorized the war. Lee, by contrast, seemed to take it all much more seriously than the King, as becomes apparent once Ayers assumes the art chores. Not that he tries for realism per se, only that scenes like the one in #3 where it requires a tank to corral the Howlers into the guardhouse disappear post-Kirby.
Finally, as will become clear later, Happy Sam has several Rangers units under his command, including Able Company (Fury's Howlers), Baker Company (McGiveny's Maulers) and whichever company was Jim Morita's Nisei Squad.
Love that you're doing this, shax! Keep it up!
I summon the chicken-scratchin' goldbrickin' lightning!