The shape of the hammer which Thor wields in this movie is actually the shape of Stormbringer, the hammer of Beta Ray Bill, an alien who defeated Thor in a duel. Odin made Stormbringer specifically for Beta Ray Bill.
Full story can be found in Thor comic issue #337 .
In this movie, Chi McBride plays "Chief Elder." McBride also plays Nick Fury in "Ultimate Spider-Man: Web Warriors." (2012)
Hawkeye, Quicksilver and Scarlet Witch were not in the initial Ultimate Avengers movie and were originally planned to be in the second movie. Using Hawkeye as an example, VP of Marvel Studios' Animation Development Craig Kyle did not want him to be a background character but "he's going to matter" if he appears.