Adventurer was the easiest, getting a mashup of talents from the Scout and Warrior classes, plus a "Combat Focus Talent Tree" that enables him to crank up his BAB.
Fixer (formerly "Shadow") gained a lot of the talents from the Rogue, plus a "Gumshoe Talent Tree" that has talents good for private eyes, such as "Licensed" and "Insightful Deduction."
Scholar, which I'm working on now, is a bit trickier. In S&S Saga scholar was a cross between a D&D bard and sorcerer; in a mystery/horror context a scholar is more like a doctor, professor, or antiquarian. So while he still gets the Lore and Priesthood Talent Trees (with some tweaking), I'm not sure what else to give them. I figure that the Adept and Hypnotism trees from S&S Saga should probably go to the Visionary, assuming that Hypnotism is left at all, and the Alchemist Talent Tree has no place at all. I suppose I could try some kind of a tree for Doctor/Psychologist types, giving them the ability to do surgery and whatnot. I'm not sure what to give them that would be more generally useful, tho — enhanced healing or the ability to mitigate SAN loss, maybe?
Socialite should be pretty easy, getting mostly stuff from the Noble and a bit of the Rogue's charming abilities.
Visionary will be tricky; I'm figuring they'll have some psychic abilities, as well as some enhanced senses or insight abilities. I was also thinking perhaps of what boils down to roughly a "Mad Science Talent Tree," although it would need a name change to fit the intended atmosphere better. (Prerequisite: SAN 30 or less?) I wonder if this might be better as a path for the Scholar, however. Was "Herbert West, Reanimator" a scholar, or a visionary? Tough call.
I'm open to suggestions!