Skip to the next post for the actual explanation or choose to cringe. 

Skylle the Hedgehog! He's fast and cool, but not like Sonic cool. He has a mellow personality, but always acts like a older brother when you need him. He can move at the speed of space if puts both rings on his legs. Twice as fast as Sonic. Whenever Sonic gets faster, he gets twice as faster! When he gets the 7 chaos emeralds he turns into Super Skylle! He's also a doctor. However, he has a deep dark side.  He was cursed as a kid to wear the braceets all the time. Should the leave him too long and he is left unchecked he will go on a rampage with no mercy. He'll become Skyde. He prefers Mr. Skyyde though.

But don't worry! He can control his dark side if he beleives in friendship. And transform into Skiddle

...

If you lived though that congratulations. But now to be serious...

Now believe  it or not, I am not trolling you here. If we really think about it, this may be the only logical option.

If we take a look at this character who does it remind you of? Probably Bubsy!... Probably Bubsy.

At this point we already know that Sonic's forest friends will be NPC's only

That limits it severely. We can already count Shadow and Silver out. We can also (unfortunately) count Adventure Sonic out. So what's left?

My original character Skyle the Hedge   The reality is that it may be a customizable character. This makes perfect sense going off of Generations.

If you look at the game on PC, there is a huge modding community behind the game replacing Sonic with Mario or Scourge the Hedgehog.

Yes, believe it or not Scourge the Hedgehog is a real Sonic character... from the comics. That is what I want to focus on. The comics. The freedom fighters are huge thing in the comics and Egg man is actually a consistent threat in that comic book. Its actually well made, borrowing a lot from Sonic Sat and the games. A lot of the times the story in the comics is much better than the games. Though as a series it can be convoluted. I digress.

 The reason I bring this up, because there really are parallels between Sonic comics and Sonic Forces. I am looking at the title of Sonic Forces as Sonic's Freedom Fighters. In this sense, its somewhat like in the comics like where you have a random anthropomorphic animal. I think the Sonic team might want to actually use this. This would certainly be a surprise that they were holding onto. Do I think its a good idea? Meh. However its a possibility...

Don't say I didn't warn you