The Epic Games Store page for Sonic Superstars has a screenshot of Amy alongside Sonic in the Sonic Act of Speed Jungle, which is not possible in the game itself since only Sonic is playable in that Act.

The Tails Doll from Sonic R can be found in Pinball Carnival Zone Act 2, floating at the end of an exploding rollercoaster. However, the coaster's momentum would make most players automatically speed past and not notice him. When you jump and touch him, he will turn into a gold coin. His inclusion in the haunted level may be a reference to his status as the subject of various creepypastas.

Despite initial belief, the intro animation was not done by frequent collaborator Tyson Hesse, but rather a Japanese animation studio using his character sheets as reference. This makes Sonic Superstars the first Sonic game to have an intro animated by a Japanese studio since Sonic Riders in 2006.

The appearance of Golden Capital Zone is based on concept artwork for the original Sonic the Hedgehog, from the appearance of the shuttle loops to the glittering temples in the background, with Japanese text in the concept art referring to it as a "gleaming, gold plated landscape with a Southeast Asian feel."

In the promotional comic "Sonic Superstars: Fang's Big Break", Dr. Eggman refers to Fang by various different names before coming to his current name of "Fang the Hunter". Each of the names mentioned is a reference to a name Fang was given in the past Sonic titles:

• "Nack the Weasel" was Fang's original name in Western regions, as well as the Sonic comics published by Fleetway and Archie.
• "Jet the Jerboa" is a reference to the name under which Fang was first revealed in Western regions (the article where Sonic the Hedgehog: Triple Trouble was first previewed in the Mean Machines Sega article, when it was called "Sonic Chaos 2", with Fang originally being named "Jet the Sniper").
• "Fang the Sniper" was Fang's original name in Japanese regions, and would later be carried over into the West via Sonic the Fighters.

The comic itself provides an in-universe explanation for the numerous name changes: being a wanted criminal, Fang has had to constantly change his name in order to keep the authorities off his toes.

As Takashi Iizuka and Naoto Ohshima were discussing the game's story, they felt they needed to introduce a new character with their own background and unique characteristics that would make them someone people could empathize with and enjoy. The character being able to fit in with the setting was of particular importance, as Iizuka recognized that previous games had a tendency to introduce new enemy characters that were very prominent and that had immediately recognizable strength/power (i.e. Infinite from Sonic Forces). For the new character, who would eventually become Trip the Sungazer, they wanted to introduce her as initially clumsy to make players question why she is supposed to be a powerful enemy.

In June 2023, the character models for the game received complaints on Twitter by fan artist Rafa Knight, who noted that they resembled her own models of the characters that had been used for merchandise, even having the same minor imperfections as the toys. She claimed she had not been credited for her work either, instead being ignored by Sega and other related figures. In response, Katie Chrzanowski, the social media manager for Sega of America, apologized for the misunderstanding and explained that the models were custom-made for Sonic Superstars, and promised to privately email Knight with more details later on. It's unknown if any more developments in this controversy happened since.

Metal Tails and Metal Amy, two characters playable in the game's Battle Mode, were created by Kazuyuki Hoshino, the original creator of Metal Sonic. Also playable in the Battle Mode is Metal Knuckles, who makes his first appearance in a Sonic game since Sonic R.

Sonic Team was surprised by the excitement towards the return of obscure characters Mighty the Armadillo and Ray the Flying Squirrel in Sonic Mania Plus, leading them to decide to bring back another obscure character for Sonic Superstars. They ultimately went with Fang the Hunter (then known as Nack the Weasel or Fang the Sniper), one of the main antagonists of Sonic the Hedgehog: Triple Trouble.