With the naughty pig, on the bit I mentioned earlier, you just have to keep away from him long enough for the Bitzer icon to flash. Then you can quickly call Bitzer over to tell the pig off.
Best way I found was to use the stylus and move Shaun to the far left, then to the far top, then to the far right, and so on. Two "rounds" is enough for Bitzer's icon to flash.
Also, I only discovered that by a fluke. I do need to find two hours to play the game again and note things down, which is why I can't help with anything specific at the moment.