I have a close friend who works in the Jakks Pacific Design Team & they've disclosed some interesting information regarding upcoming Sonic Action Figures. Take all this with a grain of salt:

Good news:
. A line of Movie-Based 4" Action Figures are coming featuring Movie Sonic, Tails, Knuckles & two Robotnik figures (one from the first film & the other from Sonic 2).
. 4" Figures of Silver, Classic Tails, Super Silver & Classic Knuckles are coming soon.
. There are plans for a 4" Super Hedgehog Two Pack with Super Sonic & Super Classic Sonic (which will later be re-released in the main waves).
. There are plans for two new 2.5" playsets in 2022.
- One being based on Radical Highway.
. 2.5" Figures of Classic Tails, Super Shadow, Crabmeat, Amy, Classic Knuckles & Jet are coming in the next three 2.5" waves.
. There are plans for figures of Chaos, Gamma, Jet, Zavok, Werehog & Classic Metal but those are VERY early in development.
. Plushes of Modern Amy, Hero Chao, Silver & Big are in development.

The bad news:
. Wave 6/Modern Amy's sales are considered too low &Jakks have decided against making any new female action figures.
- There will be no Rouge or Blaze Figures & Plushies of any kind in the line (it was believed that they wouldn't sell enough even before they found out Amy's sales).
. There are no plans to make 4" or 2.5" figures of the Chaotix:
- Vector is considered too big to fit in the regular wave packaging & they don't want to shrink him down (as he'd be too tiny to scale with the 4" cast)
- Due to Espio being Purple, it is believed that kids wouldn't be interested in buying him.
- Charmy's design isn't considered "appealing" enough.
. Due to disagreements with SEGA, there will be no more Ray merch (which is the reason the previously leaked plush never released).
. Some characters who were rejected by SEGA include Omega, Cream, Storm, the 'Hooligans', Infinite & any comic based characters.