Well, if we ever get a remaster, they could probably add them back in.Plus, I have a feeling that Sonic Frontiers will be tied in with Sonic Superstars some way or another. I mean the Special Stages, or at least possibly the Bonus Stages, they look like they take place in some sort of digital dimension. So if Northstar Island is in the vicinity of Starfal Islands or have Ancient tech on it, I wouldn't be surprised if the Chaos Emeralds individual powers were due to cyber space.
Yes, they could be tied.
Also the new character, Trip, looks like she wears something to safely travel between dimensions.. Digital dimensions may be...