Have you read up on the game as a symbol yet? Because you definitely should. We're in no rush and will happily wait.
Okay, you ready? See, the toys are kind of a sub-symbol for the game—they're the figurines that Zach, Alice, and Poppy use in their ongoing after-school game. The kids use figurines as a sort of role-playing exercise, stepping into different identities and trying them on for size. Relatively helpless in their own lives—they're pre-teens, after all—the toys are a way for the kids to explore different possibilities. Through the characters, the kids can safely explore different parts of themselves.
Of the three kids, Poppy seems to understand the connection between the kids and their toys most clearly: "Do you think that William likes Lady Jaye?" she asks. "Like like likes?" (1.56). Of course the real question is whether Zach like likes Alice. Poppy, then, sees the toys are a sort of code or alter ego for herself and her friends.
During their quest, Zach and Alice actually seem to become their favorite toys in real life. In the spirit of his pirate character, William the Blade, Zach steals a boat, and Alice becomes a wild woman just like Lady Jaye when she breaks into the library. Loosened from the constraints of their parents and daily lives, Zach and Alice dare to truly become the people they've daydreamed and played at being. And you know what? This works out pretty well for them in the end.