Disney can't use any of the characters currently features at IoA in its Orlando theme parks as long as Uni meets its contractual obligations as it pertains to those specific characters. All other Marvel characters (and there are thousands) and any newly developed characters by Marvel can be featured in the parks. Disney is developing several Marvel inspired franchises namely for Disney owned cable outlets. This is just the tip of the iceberg as Iger has big plans for Marvel. I would expect you would see character meet and greets first in the WDW theme parks especially if the new shows are ratings winners. Something along the lines of the way Power Rangers and Ninja Turtles have been featured. As for actual attractions and stage shows, that appears to be at least a few years away. This situation really creates a huge dilemma for Universal if you think about all the implications. Which is why I still predict they will drop the Marvel characters sooner rather than later. The agreement also gives Disney access to Universal's business data since Disney gets paid fees now that it owns the IoA characters.
PS- If Uni decides to convert it's Marvel based land to something like, oh say, Transformers...then Disney can use those characters (including Spidey) in WDW theme parks immediately. And all bets are off as to how fast Disney would build new attractions then.
Hope that helps.
