Linda Harrison, who played Nova in the first two Planet of the Apes movies (and had a cameo in the 2000 remake), is of no relation to former Beatle George Harrison, whose widow is Olivia Trinidad Arias.
Probably not. William Henry Harrison and Benjamin Harrison were American presidents. George Harrison was a British musician who was born after the former two.
George Harrison was lead guitarist for the Beatles. He went on to have a successful solo career after the band broke up. He passed away on November 29, 2001.