My plan to integrate the Watchmen in this universe:

[hider=Timeline]
1938 - Hooded Justice attacks his first criminal, sparking the first wave of costumed vigilantism by non-powered humans.

1939 - The Minutemen are formed alongside a Justice Society in its infancy. The original lineup of members are Captain Metropolis, Hooded Justice, Silk Spectre, Nite Owl, Silhouette, Dollar Bill, Mothman, and the Comedian.

1940-1945 - Nelson Gardner takes the Super Soldier Serum alongside Steve Rogers. Both test subjects are a success, and as Captain America leads the crusade against HYDRA in Europe, the Minutemen fight domestic threats within the United States.

1946 - The war has ended, and the Minutemen have no more enemies to fight. Captain Metropolis' inflated ego has driven many of his teammates away from him. One by one,  the Minutemen go to walk their separate paths, while Captain Metropolis remains an agent for the government.

1960 - Captain Metropolis is assassinated by a HYDRA agent in Canada. In the same year, Dan Dreiberg showcases his arsenal to a retired Hollis Mason, and is granted the title of Nite Owl II.

1964 - Rorschach kills his first criminal in New York, but is severely injured by Dreiberg on patrol, being mistaken for the criminal in question. Because of this, the two never team up.
[/hider]

Apologies if my writing isn't up to scratch, I'm a little busy IRL.