[1] He's depicted as an anthropomorphic white duck with a head of brown hair, usually dressed in 1970s-style clothes (platform shoes, bell-bottoms, et cetera).
None of the songs were by the original artists; according to the album cover, they were being performed by "The Wibble Wobble Singers and Orchestra."
[3] While numerous voice actors played Irwin throughout this series, the most notable is Don Messick of Hanna-Barbera TV cartoon fame, the original voice of Scooby-Doo and other such characters as Papa Smurf, Boo-Boo, Astro (of The Jetsons), Dr. Benton Quest and Bamm-Bamm.
His Irwin voice was similar to many Hanna-Barbera and Rankin/Bass characters, including Pixie, Scrappy-Doo and Snip (in Jack Frost).
Irwin's hair, wardrobe and DJ persona are all reflections of American radio personality Rick Dees, who wrote and recorded the "Disco Duck" song on which this series was based.