I don’t think Paramount has any hold on Iron Man. Universal has Hulk because they’ve had the rights to that character for decades (and thus why Marvel has little interest in standalone Hulks). Marvel never gave the rights for the Iron Man character to Paramount, they were always with Marvel Studios (and Iron Man 3 was the first Marvel film to only have the Marvel Studios logo). As for what sort of distribution rights Paramount still holds for the first two films, I couldn’t tell you. Anyway, whether Disney holds the distribution rights or not to those films hasn’t stopped them from packaging them along with their own in box sets (along with Universal’s Incredible Hulk), which should tell you that the kind of mixed rights distribution a Star Wars set would require isn’t impossible.