Is Marvel Studios fifth Paramount movie a potential source of dispute?

Marvel studios seems to be locked into a distribution deal with Paramount for its next five movies, but exactly what properties those movies will be about is a bit unclear. Specifically after Iron Man 2, Thor, Captain America and Avengers – what is the fifth and final film? some coverage says that it will "most likely" be Iron Man 3 (note the uncertainty) while others suggest Ant Man. Indeed when the distribution deal was first reported by Nikki Finke Ant Man was listed as the final movie.

Ant Man has been in development since 2006 with Shaun of the Dead and Scott Pilgrim writer/director Edgar Wright at the helm. Wright was still connected with the project as recently as this July and Marvel Studio's head Kevin Feige has discussed the project in numerous interviews.

I’m guessing that the idea of producing this Ant Man movie has suddenly become much more attractive to Feige – you have got to believe that if they could, Disney would seize the opportunity to own Iron Man 3 outright. Ant Man is clearly a riskier project with a narrower appeal.

Added to that are some logistical issues – all indications are that Marvel wants Favreau to direct their big Avengers movie. That means that to make Iron Man 3 the fifth film either Favreau leaves the franchise or the movie is pushed back from 2013 and the Paramount deal is extended for another few years – neither of which is too desirable for Disney/Marvel, I would imagine.

Also worth thinking about here is the fact that when this Paramount deal was first agreed it wasn't clear which of these properties were going to be the most successful – so it’s by no means a sure thing that Paramount locked down sequel rights to any particular characters in their 5 film deal. Indeed it is still possible that Iron Man 2 will be a flop or that either Thor or Captain America might be an even bigger hit, making Iron Man 3 less attractive.

One other possibly crucial detail - in June Feige revealed that another, as yet unannounced Marvel movie was planned for release in 2012, the same year Marvel/Paramount's 3rd and 4th movies (Captain America, Avengers) are due to be released. He seemed to hint that an announcement would come at San Diego, but none materialised. Maybe I'm crazy but the timing (and the probable delay in any announcement) makes me suspect that this could have had something to do with Marvel's acquisition of the Marvelman property. At any rate is this new movie part of the Paramount deal? is it even still in development?

Nikki Finke recently published a quote from Rich Greenfield at Pali Research, in which he discussed the Marvel/Paramount deal:

Marvel’s current distribution deal with Paramount (Viacom-owned) covers the next five Marvel pictures including Iron Man 2 (2010), Thor (2011),Captain America (2011), The Avengers (2012) and Iron Man 3 (2012/2013). Paramount confirmed the films to be produced under their Marvel agreement.

He apparently did not check with Marvel though. Could this be Paramount putting down markers to indicate to Marvel that they believe that Iron Man 3 is part of the deal? is it that they are actually on board with Feige's secret new film project and are just being coy with Greenfield? or could all this speculation be way off-base -have Marvel and Paramount already agreed that Iron Man 3 is the last film in their agreement?

All this reminds me of the dispute between Pixar and former Disney chief Michael Eisner over Toy Story 2. That mess took years to sort out and almost destroyed the very lucrative Disney/Pixar relationship. Hopefully all my speculation is groundless and the terms of the Marvel/Paramount deal are clearly set-out.