Originally Posted by R_Hythlodeus
By not including Pym one would actually destroy two characters: Pym, whose guilt over creating Ultron is one of his trademark characteristics, and Ultron, whose Oedipus complex is the cataclyst for his desires to take over the world.
Whedon is smart enough to know that.
However, A:EMH handled the situation guite well with Stark having a hand in Ultrons creation too. As long as it is clear, that it was actually Pyms fault, and that Pym is the main creator, there is nothing wrong with Tony working along on that project.
If Stark is made to be the guy responsible for creating Ultron, then it would also destroy *three* characters. Strongly doubt they're going to mess up The Golden Boy of the MCU that way.
Short answer: yes, Hank Pym needs to be introduced in AoU as Ultron's creator.