Yes, Jaq and Gus are different characters than Suzy and Perla. In the parks, Suzy is the one in the blue dress and Perla wears a pink/ purple dress. Jaq and Gus are indeed only in SpetroMagic at the time in character form. You can see tiny versions of them looking down from the rafters of the lobby in CRT too.
As far as the movie, only Jaq and Gus have their names mentioned in the films, but the others that bradk mentioned are also in the film too, but their names were not mentioned in the films. According to Disney archivist Dave Smith, Suzy is girl mouse with at first decides that the mice can make the dress for Cinderella ("We can do it! We can do it! We can help our Cinderelly") and Mert, Bert and Luke are the three mice that follow around Gus and Jaq when they are getting corn from the chickens. The script does not really clarify who Perla and Blossom are in the film.