1) Yes, you can use the scheme for any "big lift" as long as you know which assistance exercises to use to fix the weak link in that lift.
2) That's perfectly fine (selecting the power clean from the hang). Cleans from blocks can be a good choice if it targets a weakness of yours (are you an athlete who is very effective at utilizing the stretch reflex/rebound and do you have "instant explosion?" .... if the answer is NO then the power clean from blocks is a good choice). The pull ups are fine to do as a bonus exercise, but not as a main assistance lift since it doesn't really target a significant weak point in the clean. Clean pulls, clean high pulls or even power snatches from the hang would be a better choice.