Question: Are Alexander Hall and L. Ron Hubbard both American?

Context paragraphs:
Bare-faced Messiah: Bare-faced Messiah: The True Story of L. Ron Hubbard is a posthumous biography of Scientology founder L. Ron Hubbard by British journalist Russell Miller.  First published in the United Kingdom on 26 October 1987, the book takes a critical perspective, challenging the Church of Scientology's account of Hubbard's life and work.  It quotes extensively from official documents acquired using the Freedom of Information Act and from Hubbard's personal papers, which were obtained via a defector from the Church.  It was also published in Australia, Canada and the United States.

L. Ron Hubbard House: The L. Ron Hubbard House, also known as the Original Founding Church of Scientology, is a writer's house museum and former Scientology church located at 1812 19th Street NW in the Dupont Circle neighborhood of Washington, D.C., United States.  The home served as the residence of Scientology founder L. Ron Hubbard from 1955 until 1959, during which time he incorporated the Founding Church of Scientology and performed the first Scientology wedding.  The building is a contributing property to the Dupont Circle Historic District, a neighborhood listed on the National Register of Historic Places.

A Piece of Blue Sky: A Piece of Blue Sky: Scientology, Dianetics and L. Ron Hubbard Exposed is a 1990 book about L. Ron Hubbard and the development of Dianetics and the Church of Scientology by British former Scientologist Jon Atack.  The title originates from a quote of Hubbard's from 1950, when he was reported as saying that he wanted to sell potential church members a "piece of blue sky."

Scientology in the United Kingdom: Scientology in the United Kingdom is practised mainly within the Church of Scientology and its related groups which go under names including "Hubbard Academy of Personal Independence" and "Dianetics and Scientology Life Improvement Centre".  The national headquarters, and former global headquarters, is Saint Hill Manor at East Grinstead, which for seven years was the home of L. Ron Hubbard, the pulp fiction author who created Scientology.  Church-connected groups promoting aspects of L. Ron Hubbard's teaching, including Narconon and CCHR, have also been active in the UK, in some cases with charitable status.  There have also been groups practising Scientology independently of the Church.

Margaret Grubb: Margaret Louise "Polly" Grubb (September 22, 1907 – November 17, 1963) was the first wife of pulp fiction author and Scientology founder L. Ron Hubbard, to whom she was married between 1933 and 1947.  She was the mother of Hubbard's first son, L. Ron Hubbard, Jr. and his first daughter, Katherine May "Kay" Hubbard.

L. Ron Hubbard: Lafayette Ronald Hubbard (March 13, 1911 – January 24, 1986), better known as L. Ron Hubbard ( ) and often referred to by his initials, LRH, was an American author and the founder of the Church of Scientology.  After establishing a career as a writer, becoming best known for his science fiction and fantasy stories, he developed a system called Dianetics which was first expounded in book form in May 1950.  He subsequently developed his ideas into a wide-ranging set of doctrines and practices as part of a new religious movement that he called Scientology.  His writings became the guiding texts for the Church of Scientology and a number of affiliated organizations that address such diverse topics as business administration, literacy and drug rehabilitation.  The Church's dissemination of these materials led to Hubbard being listed by the "Guinness Book of World Records" as the most translated and published author in the world.  The Guinness World Record for the most audio books published for one author is also held by Hubbard.  In 2014, Hubbard was cited by "Smithsonian" magazine as one of the 100 most significant Americans of all time, as one of the eleven religious figures on that list.

Alexander Hall: Alexander Hall (January 11, 1894, Boston, Massachusetts – July 30, 1968, San Francisco, California) was an American film director and theatre actor.

L. Ron Hubbard, Messiah or Madman?: L. Ron Hubbard, Messiah or Madman? , is a posthumous biography of Scientology founder L. Ron Hubbard written by Bent Corydon, which makes extensive use of interviews he conducted with Hubbard's son Ronald DeWolf.  Though originally published in 1987 by Lyle Stuart Inc., the book was re-issued in a paperback edition on July 25, 1992 and a hardcover edition in October 1995, both by publisher Barricade Books.  The 1995 edition also featured Brian Ambry as principal researcher.  The first edition of the book listed DeWolf as coauthor.

Church of Scientology: The Church of Scientology is a multinational network and hierarchy of numerous ostensibly independent but interconnected corporate entities and other organizations devoted to the practice, administration and dissemination of Scientology, a new religious movement.  The Church of Scientology International (CSI) is officially the Church of Scientology's parent organization, and is responsible for guiding local Scientology churches.  At a local level, every church is a separate corporate entity set up as a licensed franchise and has its own board of directors and executives.  The first Scientology church was incorporated in December 1953 in Camden, New Jersey by L. Ron Hubbard.  Its international headquarters are located at the Gold Base, in an unincorporated area of Riverside County, California.  The location at Gilman Hotsprings is private property and not accessible by the public.  Scientology Missions International is under CSI and oversees Scientology missions, which are local Scientology organizations smaller than churches.  The Church of Spiritual Technology (CST) is the organization which owns all the copyrights of the estate of L. Ron Hubbard.

Brain-Washing (book): Brain-Washing: A Synthesis of the Russian Textbook on Psychopolitics, sometimes referred to as The Brainwashing Manual, is a book published by the Church of Scientology in 1955.  It purports to be a condensation of the work of Lavrentiy Beria, the Soviet secret police chief.  The book states Kenneth Goff as author.  Its true authorship is not clear, the three common hypotheses being: Scientology founder L Ron Hubbard, Kenneth Goff (alias Oliver Kenneth Goff), or both L Ron Hubbard and Kenneth Goff based on an acquired US agency report.  The third hypothesis is questionable as there is not proof that the two men ever knew each other.  Claims that L Ron Hubbard was the author are also dubious as the only source of this claim is his estranged son, L Ron Hubbard Jr., who made it his life work trying to intentionally discredit his father in every possible way, and in addition to withdrawing all his accusations before his death, has been discredited in courts of law.

Supporting paragraphs: Alexander Hall L. Ron Hubbard
Answer: yes