Yes! All the DLCs are compatible with both Steam and itch versions. You can find them in the Steam directory for the game. To access this, right click on the game in your Steam library, then under "Manage" click "Browse Local Files". This should take you to the main directory. In there you'll find a folder called "game", where the DLCs are. They should be labeled "dlc_step_1.rpa", or similar. Just move those rpa files into the "game" folder of the itch version, and they should work! If you need any more help, just let me know.