IMO here's the actual most likely ones
1. Eggman
2. Shadow
3. Tails
4. Knuckles
5. Metal
6. Blaze
7.Chaos
Anyone below that would probably never happen.
1. Eggman
2. Shadow
3. Tails
4. Knuckles
5. Metal
6. Blaze
7.Chaos
Anyone below that would probably never happen.
Also, Infinite isn't the "only reasonable antagonist" - Metal would work good too, if not better.