The actor who plays Sebastian on Glee just confirmed that he auditioned for the role of Finnick. So I'm guessing we might know within the next month who it is. The whole cast has to be pretty much assembled as shooting starts in November (as Jennifer has to start shooting the 2nd X-Men movie in January).
http://www.examiner.com/article/hung...-odair-casting
The article, albeit from the examiner, stated that Jenna Malone has officially accepted the role of Johanna.
And of course Mockingjay will be 2 movies (because they need to make as much money as possible). Looks like from now on the movies will be a year apart in November. Anticipated Catching Fire release is November 2013. Mockingjay pt 1 is November 2014 and Mockingjay part 2 is 2015.
Although, I'm not sure why they need two movies for Mockingjay. It's not like the book was super long like Breaking Dawn or Harry Potter. The whole book could easily be in one movie.