There were actually a LOT more Disney references than just those three cameos.
Here are some more from Wikipedia:
The storybook opening is a tribute to how Snow White, Cinderella, and Sleeping Beauty began. The book's location in the castle is based on artwork from Sleeping Beauty.
While Giselle herself has many traits similar to Snow White, Cinderella, Aurora, Ariel, and Belle, her character's personality is mostly based on Snow White.
During the initial animated segment where Giselle calls animals to her home, a frog is seen wearing a soap crown in a reference to The Princess and the Frog.
As she is building the Prince mannequin, Giselle looks through two blue gems the same way Dopey does in Snow White.
Animals often help the Princesses do chores, sewing, and other tasks. Giselle continues this tradition. She also calls the animals the same way Snow White does.
The song True Love's Kiss is a tribute to the songs I'm Wishing, A Dream is a Wish Your Heart Makes, and Once Upon a Dream. The construction of Giselle's dream prince with the help of the woodland animals is also a tribute to a similar scene in Sleeping Beauty.
Prince Edward has traits similar to Prince Charming, Prince Philip, the Prince from Cinderella, and Prince Eric from The Little Mermaid. His dance with Nathaniel is a tribute to the dance Philip had with King Hubert in Sleeping Beauty.
In both the animated and real world, Queen Narissa's transformation into a dragon is done similarly to Maleficent's transformation in Sleeping Beauty.
The way Giselle and Edward ride off into the sunset is a tribute to the end of Snow White.
Giselle's carriage is based on Cinderella's coach.
The troll is wearing remnants of other Disney Princess' dresses as a loincloth. Among the remnants are sections for Snow White, Belle, Sleeping Beauty, and Cinderella. His earrings are made from Ariels shells.
A reference to Beauty and the Beast in Giselle's treehouse is a bell jar containing a rose.
As the troll is flung to the next kingdom, he yells like Goofy.
While discussing possible places to rest while standing outside Robert's apartment, Giselle makes reference to "a houseful of dwarfs; I hear they're very hospitable."
A Muzak version of the song Part of Your World from The Little Mermaid can be heard when Giselle is gazing at the tank of fishes, and Sam the assistant is played by Jodi Benson, Ariel's voice in The Little Mermaid.
Sam is named after Sleeping Beauty's Prince Philip's horse Samson.
The divorcing couple are named after the parents in Mary Poppins, the Banks.
The name of the law firm, "Churchill, Harline, and Smith", refers to the Snow White and the Seven Dwarfs songwriters: Frank Churchill, Leigh Harline and Paul J. Smith.
The bus driver's hair is shaped like Mickey Mouse's ears.
The birdseed woman is a tribute to a similar scene in Mary Poppins.
Snow White is referenced in a number of ways: the queen sending someone to kill Giselle; the poison apples in general, and the skull emblem on one of the apples specifically; the Magic Mirror; the Magic Wishing Well; the evil witch turning into the old witch (as well as the design of the old witch); the shot of the poison apple falling from Giselle's hand; and Giselle being laid on a bier. The shot of Giselle lying on the bier is based on the same shot from Sleeping Beauty. Both Snow White and Sleeping Beauty were referenced by Giselle being woken by a kiss.
During the That's How You Know musical number, the yellow-jacketed dancer also danced as a chimney sweep in Mary Poppins.
In the bandshell, Giselle interrupts a performance of Rapunzel, an upcoming film. Some of the trees on the set are inspired by trees from Sleeping Beauty.
The soap opera shown on the television is a tribute to Beauty and the Beast: it stars Paige O'Hara, Belle's voice in Beauty and the Beast. The character she plays on the soap is named Angela, a tribute to Angela Lansbury. The other actor on the soap opera is named Jerry, a tribute to Jerry Orbach. The actors mention a third character named Ogden, a tribute to David Ogden Stiers. The background music for the show is the song Beauty and the Beast, and the set design is based on that film's bandaging scene.
Another television program with Edgar Bergen and Mortimer Snerd is a clip from the Disney film Fun and Fancy Free.
When first cut to the TV, an audio clip from Dumbo is heard before Edward changes the channel.
The news reporter, Mary Ilene Caselotti, is named for Mary Costa, Ilene Woods, and Adriana Caselotti, who did the voices for Sleeping Beauty, Cinderella, and Snow White, respectively.
The restaurant Bella Notte is a tribute to Lady and the Tramp.
The Grand Duke Hotel is named after the character from Cinderella.
In Morgan's room is a Belle doll, as well as a Cinderella storybook.
One of the residents in Rob's building is Judy Kuhn, who was the singing voice of Pocahontas.
Cinderella is referenced when the clock strikes midnight, and from the glass slipper being lost in the ballroom (and found again for Nancy).
Happy Working Song is a tribute to Whistle While You Work, and the lyrics also contain references to other films. The song's ending is similar to how Under the Sea and Be Our Guest both end.
The way the birds turn Giselle's dress into an apron, as well as the way they wrap a towel around her in the bathroom, are references to the way the birds act in Cinderella. The soap bubble reflections, the way the flies twist the dishcloth, and Giselle's use of Rob's curtains to dresses are also references to the film.
The way Giselle and Robert look at each other at the ball is a tribute to the similar scene with Cinderella and Prince Charming.
Robert's costume at the ball is the same style as the Beast's in Beauty and the Beast.
The song "So Close" is a tribute to the song Beauty and the Beast, from both the moment in the film the song is played, as well as that the song is sung from the perspective of an observer. The camera angles during the song are also a tribute to the same scene.
The confrontation at the ball is reminiscent of the one in Sleeping Beauty.
The glittery ballroom scene is a tribute to both Snow White's Someday My Prince Will Come and Cinderella's So This Is Love in how the film isolates the princess and prince from the rest of the scene.
Pulling the sword from the ballroom floor is a reference to The Sword in the Stone.
The final fight scene at the top of the tall building is a tribute to similar final fight scenes in Snow White, Sleeping Beauty, The Little Mermaid, and Beauty and the Beast. As with those scenes, it is seen with a blue hue and is accompanied by thunder and lightning. Also, the hero fights off the villain with a sword; the villain attempts to throw the hero off the building; the villain falls to their own death.
Rob's girlfriend Nancy's last name, Tremaine, though spelled differently, was the last name of the Evil Stepmother in Cinderella.
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If I'm not mistaken, I don't believe she's technically royal.
