Nice job on #2.
I too have been trying to figure out the AF on my system with dogs. I shoot Canon and found that even on servo mode with a relatively fast focusing combo (50D and 70-200mm f/2.8L IS) it still cannot keep up, reliably, with dogs running at full tilt directly towards the camera at close distances. Often the focus is a full one dog behind so I often get the 2nd dog rendered sharply.
Keep working on it to find the best method/combo that works for you
