Here's the catalog page for Tomy's 12 inch plushes.
These are supposed to appear in August of 2018. As a general rule, larger plushes tend to be able to be more accurate/better looking than smalls because there's more area to detail & the fabric behaves better when there's enough of it. It seems to be partially true here, but hopefully these are real prototypes & not final anythings because there's problems.
Obviously, the Super Sonic is just some CG stand-in so it doesn't even count. Then, look at Shadow's shoes! They're missing literally EVERY detail. And what's his pose? Is he supposed to be waving? Why? That pose makes no sense for him. Then, Knuckles looks decent, but why give him 'the side-eye'? At least his fists are big and 3D enough & they didn't skimp on them or his shoes.
Last & never least! The Dark Chao! The fans have been awaiting an actual dark-side chao plush since Sonic Adventure 2 (so, a long time) An official one WAS made in Japan, but it was extremely scarce, maybe in-company only. This one looks like a good start, however. It has the 'evil grin' expression, the red bat wings, & red limb tips. Be sure to notice the pointy 'devil tail' also. The 'head dot/ball' is for some reason a pom-pom so it looks fluffy/furry. (So, it's the only bit that's not all that accurate, but it's not that big of a deal)