The American Kennel Club (www.akc.com) has a complete description of what they consider ideal for every breed that they recognize. However, they don't recognize all breeds or mix-breeds and they are not described. Either way, they should be able to get you headed in the right direction.
No
no
no
yes you can (=
yes they can be used
no
maybe yes no
They usually have a blind person holding onto them
Dogs identify humans by their scent so you can't really say that it's offensive to them.
Nose prints can be used to identify dogs as they are similar to our fingers prints no two are alike. This can be one of many different methods to prove the identity of your dog should it become lost or stolen. Other forms of identification are microchips, tattoos, and id tags on collars.
what
Finger prints no, nose prints yes.