This (from Wikipedia) doesn't answer the question about the Jews Harp (is that originally jaws harp?) but goes some way towards the origin of the name.
“Donald Trump's paternal ancestry is traceable to Bobenheim am Berg, a village in the Palatinate, Germany, in the 18th century. Johann Trump, born in Bobenheim in 1789, moved to the nearby village of Kallstadt where his grandson, Friedrich Trump, the grandfather of Donald Trump, was born in 1869. This German heritage was long concealed by Donald Trump's father, Fred Trump, who had grown up in a mainly German-speaking environment until he was 10 years old; after World War II and until the 1980s, he told people he was of Swedish ancestry. Donald Trump repeated this version in The Art of the Deal (1987) but later said he is "proud" of his German heritage, and served as grand marshal of the 1999 German-American Steuben Parade in New York City.”