Well, here's something to see.
It's a bit of a toss-up though because these are...fairly terrible and actually quite bootleg looking, but they are Jakks Pacific's prototype plush dolls. Very fortunately though, just proto!
The only actual good doll here is the Amy Rose one because she's the only one that's somehow on-model. Tails is horrible with his mutant nose and just awful eyes. Sonic's face is messed up with small eye & 'big body', Knuckles suffers from worse 'big body' and look at those blank eyes! The fists are so tiny too...he's just nasty looking.
Eggman is ok, but the collar is clearly wrong and he seems somehow over-simplified? Super Sonic Stinks! Tiny eye, cruddy little spikes, and yeah he's classic but like, no eye shine dot? Guess not. Mighty is seen on a previous page here on Gear, but he's the same bad looking bib-belly-dot thing in this photo too.

It's like they're stuck half-way between trying to make 'chibi simple styleized' dolls and 'regular dolls' and because of that, just nothing at all works. Messed up faces, inacurate eyes everywhere, poor detailing...everybody's just so off-model.
(What's odd is that Amy is decent somehow yet nobody else is--how was that the only one paying attention?) Notice they used special crackle/shiny fabric for her skirt and shoe laces--that could be a cute thing to do for a doll.
It is great for companies to have a rough draft.
Prototypes let them do this, review & change/refine the look before it goes for sale. In this case, it seems it was a really good idea, as they're certainly not ready for primetime.