I am located in NYC, however, the Jubar family of mine were in Vermont circa 1880. Oddly enough they were there for a very short time and they had arrived from Michigan. The oddity is that My Great Grandmother Jubar married my African (Tunisian) Greatgrandfather. He was of Moorish descent,dark tawny colored skin kinky hair,etc..this is why the Jubayr/Jubar possibility seemed plausible as in America at that time interracial marriage was frowned upon.Perhaps the families found it acceptable,or on the flipside,perhaps she was estranged for it. The state of Michigan has the highest concentration of Arab Americans in the country, as well as many Jubars. The Arab Americans have been there since the late 1800-1900's.
Ibn Jubayr,the scribe from Spain, whose family is originally from Saudi Arabia,was living around 1100 ad, which will predate any of our research,thus leaving the door of possibility open for some Jubars.
Your history sounds VERY INteresting indeed and unfortunately my knowledge on Jubar's is all here in this query.