If you just looked at Marvel's new poster for Avengers: Age of Ultron, you likely noticed the team being plagued by Ultron robots (and some perspective issues). But a closer examination of the credits finally proves that the Falcon and Agent Peggy Carter will star in the film — and they might not be alone...
Yes, actors Hayley Atwell and Anthony Mackie are listed in Age of Ultron's extensive credits, confirming a few rumors and refuting a few protestations. But the really interesting inclusion is composer Danny Elfman, who's listed as providing "additional music." It might not mean anything, but it's worth noting that Elfman composed the music for the first two Spider-Man films, and if Marvel just happened to get approval from Sony to include Spider-Man in the MCU at a very recent date, when Age of Ultron was already pretty much done, but really wanted to include a brief scene of Spidey into the movie anyways, and if they needed to get a bit of music quickly for such a scene, well, borrowing a bit of Danny Elfman's score from the Raimi Spider-Man movies would be a very, very obvious choice.
Of course, Marvel could have just hired the prolific composer for a totally un-Spider-Man-related reason, and the fact that Elfman has been added to the Avengers 2 credits at this very late date shortly after the Sony/Marvel Spider-deal went down is a total coincidence.
I know where I'm putting my money. Thwip!