Earth-919 Timeline

10th Century BCE
 Hercules has adventures. [Wonder Woman #105, Journey Into Mystery Annual #1]

circa 400 AD
 Sigurd and later, his son Siegfried, have adventures. [Thor #300, Ring of 
the Nebilung miniseries]

circa 700 AD
 Beowulf has adventures.  [Beowulf #1, Captain Marvel #20]

Circa 800 AD
 Thor has first adventure on Earth. [Journey Into Mystery #83, Jimmy Olsen #55]

Mid 6th Century Era
 The era of King Arthur and Camelot.  [New Fun #3, Black Knight #1]

12th century   
 In England, Robert Fitzooth, Earl of Huntingdon, becomes the outlaw Robin
Hood.  He and his men hide in Sherwood Forest, stealing from the corrupt
rich and giving their spoils to the downtrodden poor.  [Robin Hood Tales #7,
Young Allies #7]

 Kit Walker becomes the first Phantom. [The Phantom #1, Lee Falk's The Phantom #1]

16th century 
 Three Musketeers active. [DC Special #22, Three Musketeers Movie Adaption]

19th century
 Victor Frankenstein creates a monster.  [Phantom Stranger #23, Silver Surfer #7]
 The man known as Captain Nemo has adventures.  [Marvel Classic Comics #4, 
Young All-Stars #16]
 Sherlock Holmes has adventures as a consulting detective.  [Sherlock Holmes #1,
Marvel Preview #5]
 Mina Harker encounters Count Dracula.  [Tomb of Dracula #1, Superman #344]

 John Carter has adventures as a warlord on the planet Mars.  [Tarzan of the Apes #207, 
John Carter, Warlord of Mars #1]

 Sir Denis Nayland Smith and Dr. Petrie first cross paths with Dr. Fu Manchu.  
[Detective Comics #18, Special Marvel Edition #15]

 John Clayton, Lord Greystoke, becomes known to the world as Tarzan.  [Tarzan 
of the Apes #207, Marvel Comics Super Special #29]

 Hugo Danner has a brief and tragic career as an adventurer.  [Marvel Preview #9,
Young All-Stars #10].  Whether he has a son who succeeds him is unknown.
 Roger Kirk dies under mysterious circumstances.  [Supernatural Thrillers #1]

 Kent Allard has first public case as The Shadow.  [The Shadow #1, The Shadow:
Hitler's Astrologer]

 Doc Savage has first public case.  [Doc Savage #1, Doc Savage #1]

 The archeologist Indiana Jones uncovers the Arc of the Covenant. [All-Star Squadron #6,
Marvel Super Special #18]

 A plant creature forms around the skeleton of Roger Kirk, becoming It, the Thing 
That CouldnŐt Die, and wanders around a swamp interacting with members of a local 
family.  [Supernatural Thrillers #1]

 James Bond has first public case.  [Showcase #43, For Your Eyes Only #1]

 Calvin Elroy becomes Paragon, champion of Capitol City.  He battles a variety 
of villains, including Dexter Dorbolak, Dork the Disruptor, General DeKay, and 
Repello.  His occasional consort is t.v. anchorwoman Kora Kane.  [Captain Britain Monthly #1]
 Ken Clarke becomes Captain Krypton.  [Excalibur #50]
 Mark Milton becomes Hyperion.  [Hyperion #1]
although the American origin of Paragon and the greater detail known of him 
inclines me to prefer him over the others.

 Bruce Spector becomes Moon Man, champion of Crescent City.  [Marc Spector: Moon Knight #42]
 Dr. Jeffrey Austin is a mild mannered veterinarian who, in a bizarre 
scientific experiment gone awry, becomes endowed with the adrenal glands of a 
Doberman pinscher giving him the super powers of a dog (super strength, super 
speed, super hearing, super smell).  His occasional consort is Penny.  [Mad Dog #1]
although being able to use the 1986 entry inclines me to prefer Moon Man.

 Barry Allen becomes Fastforward.  [Quasar #17]
 Carson & Sara Hill become The Falcon & Greywing.  They solve many cases 
including "Five Dooms to Save Tomorrow."  [Alter Ego #31]
 Moon Boy has first case assisting Moon Man in Crescent City.
 Buddy has first case assisting Mad Dog.
 Joseph Ledger is contacted by a representative of the alien Order of the 
Black Sun, and has cases as The Black Sun.  [speculation]

 Simone Williams is granted powers by the Norse gods and becomes Wonder Woman.  [What If #35]
 Reed Richards, Ben Grimm, Susan Storm and Jonathan Storm, narrowly escaping 
a rocket crash, decide to make the most of their borrowed time and become 
informally known as the Reed Richards Rocket Group.  [What If #36]

 Ted Sallis is working on a biorestorative formula when an accident transforms
him into the Man-Thing.  [Savage Tales #1]  

 Luka Cage becomes involved in an experiment on prisoners to duplicate the
para-abilities of Paragon/Captain Krypton and becomes Power Girl.  [What If #35]

 Dr. Karl Oheimer, working on some brain cell regeneration drugs, is abducted 
by the CIA, who tell him about Ted Sallis/Man Thing and get him to test his 
drugs on Man-Thing in the hope that Sallis can eventually recreate his serum.
The creature regains Ted Sallis' brain; in the end, he becomes afraid and self-
immolates.  From his remains and an animal of the swamps arises an Alligator-Thing 
to act as guardian of the Nexus of Realities.  [Swamp Thing V2#1; What If #26]

 Bruce Spector comes out of retirement in Skyline City, under the name
Dark Moon. [Marc Spector: Moon Knight #42]

Note: Earth 919 was originally proposed by Ivan Schablotski, and consists of alternate-Earth counterparts of DC characters as published by Marvel Comics. Thanks to Scott Hutchins and Darren Schroeder for the Man-Thing material. Links to other Earths: Angor: in Homage, Marvel at DC (the Assemblers/Justifiers)
The Squadron Supreme - Spenser's page
The Squadron Supreme FAQ Page includes a bibliography and chronology.
The Squadron Supreme, Other-Earth's Mightiest Heroes - Paulo Costa's page
The Quarter Bin: Superheroes in the Age of Agnew (Squadron Supreme)
The Quarter Bin: The Libertarian Message of Squadron Supreme