There are 4 main dog characters..
Trixie
"pidge"
Because he is a tramp, Tramp is not giving an exact name. He briefly explains to Lady in one part of the movie that, "I have a new owner for each day of the week", and they all apparently gave him different names, but other than that he is simply Tramp. The spaniel is called Lady cuz it lives in a very posh house
Huckleberry "Huck" Hound .
he called her a tramp, by the eigth's moon night