What was specific about his painting technique was that he would always try to involve the viewer of the painting by drawing eyes and the positioning of his characters in such a way that it always seems as if they're maintaining eye contact with the audience. This was done using various perspectives and is kind of like an illusion, similarly to how the Mona Lisa is painted.
I personally love to use many of these apps! All animation movies apps are good to use!
Just left to my own devices, I would have picked Stretch and/or Squash. The next closest thing (out of those three) is exaggeration. When you read the description of exaggeration, you find that physical characteristics can be exaggerated, but they should resemble some form of reality.
The second one is really a very close call. You could make a case for either secondary action, or follow through. The only one you could eliminate is pose to pose. That is reserved for how the action goes from one pose to another. That is more of a problem in technique than overall plotting. I think I'd pick follow through, because the character has stopped bouncing the ball, but he likely hasn't stopped sweating nor looking at his watch.
Pretty interesting question. You are not going to get asked that every day.