Did you know that you can crossover different characters in each playset?
For example, you could use Iron Man in the Spiderman playset and so on. You could use Nick Fury in the leaked Guardians of the Galaxy playset!
The neat thing about it is that there will be some kind of cutscene or explanation of why they are in the playset! Only Marvel characters can do this though.
I read about it here:
http://www.ign.com/articles/2014/06/12/e3-2014-marvel-comes-to-disney-infinity-20 (Quoted below)
So it is entirely possible that you can use Agent Coulsen in the Avengers set anyway!
Think about how you could have Star-Lord team-up with Hulk to beat Loki, only to then to be Iron Fist and Black Widow taking down Green Goblin!
I haven't heard much about this, so I thought it would be appropriate to post here!
EDIT: Here is a direct quote from the IGN article: "Since these characters are all part of the same franchise, Disney’s even allowing for Marvel characters to cross playsets. If you find, for instance, ten Iron Man tokens while playing in the Spider-Man set, you unlock a story sequence that neatly introduces Iron Man to the playset and allows him as a playable character."