Yes and no.
Leavitt is actually originally not a Jewish name. It is an English name that comes from Livet, a region in Normandy, France. Vikings conquered the area and a particular family had taken up the name by the time of The Battle of Hastings 1066, when William the Conqueror invaded England.
However, many Jews bear the name Leavitt because of a misunderstanding at Ellis Island, New York, during the Emigration era of 1880-1920, since the name Leavitt sounds a lot like the Jewish names Levi and Levine. Because of this error, you can somewhat argue that Leavitt is now a Jewish name.
Douglas Leavitt's birth name is Abram Leavitt.
Sam Leavitt's birth name is Samuel Leavitt.
Steven Leavitt's birth name is StevenLaneLeavitt.
Sharyn Leavitt's birth name is Sharyn Lane.
The asteroid named in Henrietta Leavitt's honor is 5379 Hamp-Leavitt.
Norman Lear's birth name is Norman Milton Lear.
Jonathan Leavitt died in 1830.
Wendy Drew's birth name is Barbara Leavitt.
Bud Daley's birth name is Leavitt Leo Daley.
Roswell Gilpatric's birth name is Roswell Leavitt Gilpatric.
Yes.
Yes. They are cousins.