As for the "spinning the scythe and balancing it on the sword" thing... yeah, it's impossible, but you can't say it doesn't happen in other fictions. I've seen people spinning Poké Balls on their fingers as if they were basketballs... impossible (or at least very difficult) given the Poké Ball's size. I've seen a scythe itself spun unrealistically in Soul Eater.
A protege is a basically an apprentice or student.
As for it being uncommon, that is the very definition of prodigy. If everyone was that advanced then all that would mean is that the average would go up (the skill-level considered "normal" would be higher than it currently is), and a preson with prodigy-like skills would not be a prodigy but simply "good for his age".