I'm guessing the "running" one is CG.
First teaser must have been CGI. ;D
My guess is that it's a mix of CG and not in the movie. The actual BB 8 may not be able to move that fast.
They gave an official statement months ago that the shot from the first reveal was a real practical effect shot and that they had actually built the droid.
I'm not sure why people are so surprised, it's nothing that can't find in college engineering departments.