>How is it Hip-Hop if there's singing instead of rapping?

it's still rhyming couplets. it's still has the repitition inherent in most hip-hop tracks.

and about your theory, where do you place Steinski's work? DJ Shadow? Petestrumentals? Not hip-hop b/c there's no rapping? Was Kool Herc not hip-hop until Coke La Rock hopped on stage? LOL.

What about Cold Crush Brothers and their harmonizing? They're damn near the Temptations sometimes. Ha.