The fact that Earth-A and Earth-D (I assume this is the one seen in DC COMICS PRESENTS with a black Superman?) have Green Lanterns does not necessarily indicate that they also had an Oa. There was a Green Lantern on Earth-2, but he had an origin that was completely different from the Earth-1 Lantern.
Even if there are Guardians mentioned, perhaps they don't live on Oa, they inhabit an adjoining planet from one at the center of the universe. Alternatively, maybe the Guardians only LOOK like the Guardians of Earth-1; maybe they're really EVIL SQUIDS OUT TO KILL EVERYBODY! (With illusion-powers naturally, that keeps everybody trusting them; the GL Corps in that universe are all EVIL beings, in disguise as heroes as a part of a plot for universal domination).
If a character is from another company and doesn't have instant icon status, they are considered canon fodder for every crisis that comes along. Look at Freedom Fighters. Look at Blue Beetle.
There was a story that the Timely publisher (Timely being the company that in the 1960s became "Marvel Comics") was offered $50,000 in the 1950s by DC, several times, for the rights to Captain America, the Human Torch, Whizzer, and Sub-Mariner. At the time, superheroes were on the out, and this was being unreally generous for characters that Timely wasn't even publishing. This publisher, a shrewd guy said, "nah, I'm already a millionaire, I don't need the money. I like these characters; in fact, I think I'll hold on to them."
And a good thing too - instead of being shoved in the back of a JSA group photo or used as one or two time guest-stars in Roy Thomas's ALL-STAR SQUADRON before being killed outright at a future crossover as cannon fodder deaths (as these Marvel heroes undoubtedly would have been) they were instead brought back and handled with incredible style by Stan Lee and other writers as the centerpiece of a Marvel Universe: Captain America as the leader and big shot of the biggest team of heroes in Marvel except the FF, Namor as possibly the most compelling, sympathetic, original, and charismatic villain ever created, and the Human Torch as the conceptual forebear of one of the greatest heroes in the Marvel Universe (Johnny Storm), as well as being a part of a fascinating backstory involving another great character (the Vision).
Alan, in the Golden Age, got his power from a meteor, easily made an Oan construction -- but then again the Speed Force is an easy step too, but it all depends what you like and who you demonize...
OUCH! OW! :hit:
I assume that was directed at me, Matter-Eater-Lad, and my lengthy anti-Speed Force crtiques in the other forum? I've never demonized anybody, I'll have you know. I just don't agree with some ideas put out by some writers, some of which are counter to the spirit of the characters and world they are writing in.
(The exceptions of course, are Ellis - who is so smug and smarmy and venom-filled disproportionate to his actual non-talent, that I absolutely loathe him as a human being as well as a writer. Ditto for Captain Johnny Redbeard; doesn't
everybody have a "Byrne Behaving Badly" story?)