As for where the various Golden Age heroes fell along the DC/AA divide, it goes as follows:

DC: Air Wave, Aquaman, Batman and Robin, Crimson Avenger and Wing, Dr. Fate, Dr. Occult, Green Arrow and Speedy, Guardian and The Newsboy Legion, Hourman, Johnny Quick, Liberty Belle, Manhunter, Mr. America/Americommando, Robotman, Sandman and Sandy, Seven Soldiers, Shining Knight, Spectre, Starman, Star-Spangled Kid and Stripesy, Superboy, Superman, Tarantula, TNT and Dyna-Mite, Vigilante, Zatara

AA: Atom, Black Canary,, Dr. Mid-Nite, Flash, Gay/Grim Ghost, Ghost Patrol, Green Lantern, Hawkman and Hawkgirl, Johnny Thunder. Justice Society, The King, Little Boy Blue and The Blue Boys, Mr. Terrific, Red Tornado and The Cyclone Kids, Sargon, Whip, Wildcat, Wonder Woman

Hope that sheds some light on things!

I don’t recall ever seeing him mention, “I picked these characters because I had worked with them at All-American Comics in the 1940s,” and you figure that’d be something he would mention, right (again, taking into consideration that he could have said this in an interview I just never read)?

Maybe it wasn't a conscious thought of his, he just took the characters he was most familiar with, the one's he knew enough about to keep what worked and jettison the rest, without ever thinking about why he knew enough about them.

The Golden Age Robotman appeared in Star Spangled Comics. I think that's National rather than All American.

But yeah, if they'd introduced new versions of National characters like Sandman, Starman, Dr. Fate and Hourman to kick off the Silver Age, it might have gone pretty differently.

(I'm not saying Johnny Quick because he only finally disappeared two years before the new Flash was introduced and could easily have gone on with his business the same way Aquaman did.)

The Human Torch: Johnny Storm was totally different than the android version. The Golden Age Torch came back, but so did the Golden Age versions of the All-American Comics characters, so I think it counts as a reboot.

I don't think the Vision counts, necessarily, but I will note that the Avengers character was co-created by Golden Age-fetishist Roy Thomas, probably the only writer to remember the Golden Age Vision.

The secret REVEALED! The mystery UNDONE!

Julius Swartz will now have to ingest the cyanide pill he's kept in his molar for over 40 years.

...er... sorry.
Got carried away there.

Perhaps Julie, as a creator, HAD other concepts in his noodle for those characters while he was working on them, or would bounce ideas around in his mind over the years.
Then, when he had an opportunity to try them out, he went for it.
Makes sense. He had worked on those entities, had working knowledge of them, their backstories, what made them work, what didn't... Hmmmmm.

But, It DOES strike you as an odd coincidence (IS IT a coincidence?!?)...
Dun-Dunn-DUNN!!

Nice catch.

~P~
P-TOR

That said, I think it actually is probably just a coincidence, only because in all the stuff I've read about Schwartz rebooting these characters, I don't recall ever seeing him mention, "I picked these characters because I had worked with them at All-American Comics in the 1940s," and you figure that'd be something he would mention, right (again, taking into consideration that he could have said this in an interview I just never read)?