would a derse-dreaming witch of space be less passive from the beginning (i.e. not jade with her super passiveness at the beginning of the story)? i have a feeling that they would act somewhat like feferi or even damara, both derse witches

They’d be more active, yes. Remember- Jade’s LIVED on Prospit most of her life. Even with another Witch of Space from Prospit, Jade’s spent an INSANE amount of time in Prospit, since Vriska put her to sleep often. Derse influences activity. Prospit influences passivity. If you dream in the Moons, you’re likely to pick up on little bits and pieces of the culture there. So being more active-acting than Jade at the beginning of the Story is. Easy for a Witch.