I have been experimenting with creating a game where I control two characters at once. It took me a while to figure this one out, so I have created a tutorial to help others that might be struggling with the same problem…
I have also added a third tutorial in this series. This one describes how get a reference the two characters in the level blueprint, and how to control the camera to point in the middle of the two characters. http://youtu.be/35_EQ_CjVG0