generally - yeah. I want to emphasize that powerlifters also have 'efficient' muscles - in that they are recruiting a high % of their muscle fibers and that they are strong as hell. They would probably have advantages over weightlifters in the realm of
strongman style movements as these require massive
strength ; the best strongmen will also be the most powerful (because they will be able to perform their tasks, event objectives the fastest).
The weightlifter trains to perform for only a few instants (the duration of how long it takes to clean, jerk, snatch). The duration of a powerlifter's work is longer ie It takes much longer to perform a squat at 100% capacity than a snatch or jerk. The training of each as well as muscle adaptations are therefore different.
Here's a little image
Which of these athletes *look* stronger? Which of these athletes *are* stronger?
*not* heavier. The muscle itself is no denser or heavier, at most they are more efficient - meaning that neurologically they are adapted to fire faster, more muscle fibers -- but the muscle ounce for ounce weighs the same. The difference between the two is that the bodybuilder is not training to be stronger or more powerful, he is training for more muscle *mass* - strength and power athletes are not attempting (solely like the bodybuilder) to add as much mass as possible, but rather be stronger, more powerful. There does reach the point where in order to become more powerful, stronger additional muscle mass is needed.
er... that is a little too hyptothetical for my taste

and no - additional range of motion for the sake of range of motion I would argue isn't as efficacious as training the universal strength and power facilitators: the core, the hips and legs. Raising a kettlebell behind your ear with one arm won't make you stronger than someone who instead spends their time squatting; the reverse actually. Though you will be much better at raising a kettlebell behind an ear than they will be.
I will say that weightlifters have tremendous mobility. Try doing
this. Or
this.