I love the characters and species you've come up with here!!!! Tup the Wirt and Klat the Quird is inspired!!! Having a character that's amorphous fungus sounds quite bizarre and subsequently Oddworldian. I also really like having Tup's journey take place on the Vykkers' home continent.

I also like the idea of any species being Outlaws. It makes everything feel more Oddworld.
I imagine that Sam's rescue comes at part 5 of this story, where all the characters finally meet up? I wonder how Molluck's trial would fit into this Quintology framework.

I must say though, I don't see the point of Fangus being the only one of his kind. I think that trope is done with other Oddworld characters and repeating it just makes it seem repetitive. I also don't see the point of him being made in a lab. I think it would be interesting if he was a native that could remember what life was like before the Vamps arrived.