If the rumour is true (Sonic and Amy were childhood friends) then it could be legit (the fact that there are baby toys of them, not the design).
Not sure how I feel about retconning Sonic's backstory that they've always been childhood friends. I mean,
Serena from Pokémon comes to mind where she was Ash's childhood friend long before Ash set out for adventure with Pikachu. And given Serena had childhood crush on Ash, this allowed her to sort of had the one-up against Misty when it comes to shipping.
Other than that, the start of Sonic's first movie shows Sonic and Longclaw living a rather secluded life on an island. With Sonic running across the island we don't see anyone else, even though Longclaw warns Sonic not to be seen.