When Whitney Frost is in Howard Stark's laboratory, she looks at one of his designs and comments on a "palladium core". Early versions of the Arc Reactor used a palladium core.
The code Jarvis enters into The Jitterbug (a non-lethal concussive device) is 342434. Due to Howard Stark being a notorious womanizer, these numbers are in fact a famous woman's measurements (34 inches - 24 inches - 34 inches). The AMA (British Association of Model Agents) uses these specific dimensions (and a height of at least 5'8") as a recommend template for their models.
When Vernon Masters prepares to "interrogate" Dottie Underwood, he brags he tortured Ilse Koch, the Witch of Buchenwald. Koch is, indeed, a historical figure, wife of a Nazi concentration camp commander, tried for war crimes, who killed herself in custody in 1967. But at the time US forces arrested her in 1945, she and her husband had long been removed from their posts and tried for corruption and murder by a German court. Her husband was executed shortly before the end of the war. Ilse Koch was no doubt a sadistic person, but never involved in decision-making, management etc. So there was very little useful information Vernon Masters could have extracted from her ...
When Whitney sees Stark's designs for the arc reactor, she mentions how he's wasting his genius on making movies. Howard Hughes, the brilliant engineer who Tony Stark was based on, also produced and directed movies.
Peggy Carter states that Dottie is in the Santa Clarita Valley near a place called Newhall. Disney's Golden Oak Ranch is located in Newhall in Santa Clarita.