Short answers, pulled from the story.
German anthropologist Ernest Borneman claimed to have coined the phrase in a Melody Maker magazine column between 1933 and 1960. The term emerged from the fading waves of late 1950s rock and roll.
Bill Harry founded the Liverpool music magazine named Mersey Beat in 1961. He stated he derived the name from a policeman's beat instead of musical beats.
This specific rhythmic pattern originated in clubs within the St. Pauli neighbourhood of Hamburg, West Germany. English bands including the Beatles performed there during the early 1960s where locals called it mach schau or make show beat.
The Beatles appeared on The Ed Sullivan Show shortly after achieving national success in Britain. Their appearance triggered chart success across North America starting in 1964.
Phil Smee coined the term freakbeat in the 1980s as an English music journalist. Freakbeat developed as a harder-driving subgenre mainly by mod-following British groups during the Swinging London period.