With this logic, Classic Sonic is a time clone, right? This means that alternate versions and Time Clones are one and the same. “Fixing time” because of Sonic’s speed isn’t fixing time itself, rather just restoring the areas that have turned static, similar to the characters you encounter in Generations
Kinda. Classic Sonic in Generations is a time clone of Modern Sonic from the past, until he isn't anymore due to making decisions and learning things that change his course of history moving forward. He became his own distinct individual from Modern Sonic at this point, which makes them different in Mania and Forces.
Tails explains in Generations that the Sonic's running through time and space fixes them. Eggman later explains that he used the Time Eater to undo his previous defeats from history. As such, the "fixing" Sonic is doing is restoring time and space to what it was before.
Little Planet is close by because Eggman rebuilds Metallic Madness. There’s not much argument there. Creating illusions of the original Metal Sonic would not be as efficient as the original because the original has that drive to be better than Sonic
We do see Little Planet nearby Lava Reef, but it's unclear whether this is the real Little Planet or a copy of it made by the Ruby. Ultimately it's a moot point however, because making illusionary copies is incredibly easy with the Ruby. The illusions are just like the originals in every way. The Zavok illusion in Forces still has his personality for example. As such, the illusionary Metal Sonic would still have the same drive to be better than Sonic that the original had.
Again, this is all false because the Death Egg Robot is fought in a different part of the Death Egg (an elevator) and the Egg Dragoon is fought in a circuit either in or close to Eggmanland. History doesn’t get restored by winning these fights since we know for a fact that Shadow and Silver’s fights are actual rematches for the Chaos Emeralds. The only one that doesn’t follow this same rule is Chaos, but that’s just Station Square being plucked out of its timeline
The Eggmen altered time. Yes, the locations are a bit different, but it's still during the events of the original games that these rematches take place. It's just versions of history where Eggman never lost, which get undone by Sonic winning the fights.
Shadow and Silver's fights are also rematches, but in the same kind of way. Sonic is actually rebattling Shadow on the Ark during the events of SA2, and Sonic is actually fighting Silver in Crisis City from during the events of Sonic 06. It's just not the Shadow and Silver from those games he's fighting. Metal however is different. You can tell from his design that this isn't Metal Sonic plucked out of Modern Sonic's time, so this is Metal Sonic from Stardust Speedway being rebattled in the very same Stardust Speedway.
Because then they would also be meddling with his plan in CD that could be successful if they’re able to gain full control of the Time Eater. If they get Metal from before his fight in CD, then there’s a chance that Sonic can’t be defeated in CD after their supposed success in Generations
The Eggmen created versions of history in which they never lost. The Sonic's travel through these histories, and through their running and fighting time and space is restored to what it's meant to be. As such, by defeating Metal Sonic in Generations, Classic Sonic restored the fight back into what it should have been during CD.