Most, if not all, mammals can be infected with rabies. Worldwide the most common carrier is dogs. In the US the animal most likely to infect humans is bats. Raccoons and skunks are also common carriers.
Potnetially, yes. Foxes are one of the more common carriers of rabies. In the absence of rabies, a fox may still prey on smaller pets.
Such animals are called as carriers. Most dangerous thing is that some dogs are found to be carriers of rabies.
Stay away from it, as they can be carriers for rabies.
Rabies is very common.
Rabies
All animals can carry rabies, except for the hyena, which is immune to it, but can still carry it.
Yes, in fact they're one of the biggest carriers of it. They can't *contract* rabies, meaning they have it, and can spread it to people, but don't get affected by it themselves.
Bats can carry rabies, very few bats actually are carriers and again very few incidences of rabies in humans because of bats.
It depends upon the country. Rabies is not present in Australia, so possums and rats in Australia cannot get rabies. In North America, opossums rarely contract rabies (see the related link below for one documented case), but rats can certainly be carriers.
In terms of wildlife in the US, the most common reservoirs of rabies are skunks, raccoons and bats, although any mammal can become infected with rabies. In terms of the dog population of the US, it's a bigger problem in wild or feral dogs than in pet dogs.
Rabies can infect any mammal. However, most mammals, and most bush dogs, do not have rabies.