The story
Attested as a style of dance since at least January 1966 (and found in the titles of many songs around that time), perhaps from boogie (for the ending, compare crackaloo, hullabaloo). (Compare Spanish bugalú, the Spanish name for the style of music and dance.) Kent Harris used the stage name "Boogaloo" in the 1950s. The sense "sequel or repetition" refers to the title of Breakin' 2: Electric Boogaloo (1984), a sequel which was considered to be so bad it became a cult classic. Compare the sense "black person" to boogalee, a term for a Cajun, attested since 1960 or earlier.
Etymology from Wiktionary, CC BY-SA 4.0.