Re: Easter eggs?
All the talk about the mysterious "Phase Two" is a reference to Kevin Feige's classification of the films. "Iron Man" through "Marvel's The Avengers" was the "Marvel Cinematic Universe Phase One". "Iron Man 3" presumably through "Marvel's The Avengers 2" will be the "Marvel Cinematic Universe: Phase Two".
A little bit of teaser work there throughout the film.
The Avengers..The New Avengers
The Guardians of the Galaxy..The Defenders
MARVEL'S THE INFINITY WAR