Hey! Great question, and a great catch!
The DLC characters are all in very early development, so none of them have been released yet. I'm back and forth on whether I want to wait until the character's side story is complete before releasing, or to release them in steps like I do with the main campaign. When they are available, they will be posted as separate Itch projects, as Itch STILL does not have a DLC function. I do need to define which Patreon tiers will get access to the DLC characters for free, just for supporting, so thank you for catching that.
I'm also easier to reach via Discord, so don't be a stranger if ya have more questions!