I see what you mean, but I think trying to keep up with all the details you missed the spirit of the thing.
Weight shifting at the hips is the big thing you're missing, you probably missed it because it's sorta hard to envision in side walks, it's much easier to do in front walks. You have your model handy? if you do watch the way she finishes her step. That moment when she puts one foot down, and gets ready to lift the other is THE big thing. that's what makes all of us drool. Basically it's just the butt shaking from one side to the other because one glute relaxes and the other tenses.
I think the best refference for this is probably one of those rapper vids with girls walking in semi-slo-mo....sad but true :p