the movement for that pullcounter was extremely subtle the motions Floyd does after he lands his pullcounter are based on his feet. He gets out the way asap after landing to avoid return fire. I haven't seen other fighters pullcounter this way
He prepares himself with his feet, just like you described, but he actually leans out of the punch with his upper body. In my gym and with other fighters, pulling for a counter usually means leaning back with your head level and leaning your body back, taking a step back possibly, in order to avoid the blow before following up with the right hand. Floyd's pull-counter is very particular, he sticks his head up with his chin in the air and moves his feet afterward.