Hermione of course has great scholarly talents in canon. Harry -- I've seen people argue that he would have been a genius in canon if the abuse didn't warp him, and here he obviously had an excellent environment for developing mental abilities. But Harry does see himself as an anomaly. Some people here (apparently not believing nurture can explain that much) have a theory to account for him. As for Draco and Blaise, we know for a fact the former had extensive training. On a meta level, increasing Harry's intelligence required a smarter Voldemort and thus a smarter Dumbledore. Lucius Malfoy then needed smarts in order to produce a more-or-less canonical starting point for the story. And his erstwhile (?) Lord would not pick an idiot as a servant (not if he could find a way to control a smart minion.) Notice this means that, if MoR!Voldemort affected Harry's intelligence, three out of the four names you mention would have an indirect causal link in-story as well as in reality.