Woo Ha!!

The Coming Busta Rhymes
To move about excitedly as if dancing to Caribbean folk music.
Apollo Creed was the opponent to Rocky in both Rocky I & II. He was the heavyweight champ. Busta is saying that he will knock you out like the great Apollo Creed.
Arm J
Busta Rhymes is declaring that he's the Top Gun (the best) which is the name of a Tom Cruise movie. He will then metaphorically "shut down your firm" (destroy you). The Firm was also a Tom Cruise movie, where he shut down a corrupt law firm.