Those are great photographs.
I especially like the ones which show the adults and the cubs, and which demonstrates how small the cubs are, since even adult foxes aren't all that big.
I've found some of the urban foxes to be incredibly cheaky, and to barely take notice of humans. They certainly don't see us as much of a threat. Once, on an early morning ride to Greenwich to meet up for the start of a ride, when I was stopped at a traffic light, one urban fox actually started to trot towards me. I assume that (s)he had possibly been fed by someone, so was not only accustomed to humans, but saw them as a source of food.
Much as they look incredibly cute, and naively may appear to be potential pet material, I suspect your average fox is crawling with pests, and would probably be more than happy to demonstrate teeth and claws to you, if cornered. Whilst to our eyes then don't look massively distinct from cats and dogs, I imagine their lack of millennia of being associated with us, doesn't lend them to domestication to quite the same degree.