Those are my brother-in-law's family's dogs, a mastiff cross and a shitzu of all things, but he loves playing with them.
As for pulling, the practice is for actual competition where both weight pulled and time taken (distance 20feet) are taken into consideration. Dogs are put into catagories by weight so there's some little dogs in the group (its amazing to watch a 12 pound italian greyhound pull 100+ pounds without so much as blinking, it really is). At home we'll probly translate that to pulling a cart around the yard to help with stuff.
He LOVES his pool, its really funny, it was the best $10 I think I've spent on him yet!