We're glad you love the game so much! As far as the DLCs go, you do not get Steam keys from itch. Instructions for how to add the DLCs to the base game are on the pages themselves, so hopefully that helps!
For the plushie, unfortunately, that design won't be returning. Makeship, the company we worked with, rarely re-releases the same plushie. But one day we might have a different plushie design.
Hope you have a great day! And thanks so much for enjoying the game.