| Fredrik |
I've seen "Molthuni" in print: "Most free Molthuni halflings live and work in one of the many farms and ranches, proudly seeing themselves as essential laborers who keep the country independent and prosperous." Halflings of Golarion, p. 12
ETA: Whoops! I looked up demonym and you mean the noun form, like "Chelaxians" (as opposed to "the Chelish nobility"). Sorry, haven't noticed that usage -- and I've kept an eye out, due to having a Molthuni halfling character. They seem to consistently just use it as an adjective.