Other than the usual and compulsion, Vampires aren't anything special. They technically die and come back, so they can appear dead briefly upon being "killed". Oh! Vamps have the threshold rule too. They need to be invited into owned property.
As for blending in and such, its really for whatever they want to do. I won't lie, I think it'd be pretty damn convenient for undead and undead related beings to have access to a place like a mortuary. Accidents happen, after all, and that stuff needs covered up, ya dig?
I like your ideas, but I'm iffy in demons. Mostly because they are often considered extremely powerful. I want things fairly balanced so we don't have characters majorly lording over others. Then again, not all demons are uber strong Nonetheless, almost any kind of character you want.