<Graham Specter>
Unknown roles, unknown roles, unknown roles,
*Starts hitting barrel with a monkey wrench*
unknownrolesunknownrolesunknownrolesunknownroooooooooooles.
</Graham Specter>
Okay. Unknown roles.
Imo, speculating whatever these roles might be without any leads almost always proves to be a fruitless endeavor in my experience. There can be anything. Forensics, Frankensteins, Masons, Twins, Forensic Frankenstein-Twin-masons. Of course we could look at the known roles and try to decide "HMM. WHAT WOULD MAKE SENSE?" and we'd end up nowhere. True, there could be a second cop and doctor in there. Though that second 'cop' might prove to be a 0% Foo Cop (Investigations fail, turns up as scum on death. You get my drift.) Apart from that, what if our host put in nonsense/over/under-powered roles in there to throw is off track? Or what if he knows that we'd think that and put in totally normal roles? It's like meta-WIFOM!
TL;DR: I have no idea on what those hidden roles might be, and I don't think it'll be that easy to figure 'em out either.