"But hasn't all the musical practice indelibly shaped Chua's children's characters? Highly unlikely."
is supported by three claims, and when you follow the links that support turns out to be rather shaky.
Claim 1: "Behavioral genetics finds roughly zero effect of parents on personality."
Supporting link: http://econlog.econlib.org/archives/2010/01/implausible_wim....
The claim is implausible (if such parenting can make the kids neurotic, other personality changes must certainly be possible), and the link is to an article where the blog author is not convinced by a book arguing the contrary of this claim. The argument is roughly analogous to saying the heliocentric theory has zero credibility because "De revolutionibus orbium coelestium" didn't contain enough measurements.
Claim 2: "contrary to teachers' fantasies about changing their students' lives, learning is highly specific"
Supporting link: http://econlog.econlib.org/archives/2011/01/the_case_agains_...
The study cited here seems to show that German students who take Latin as a foreign language perform no better on general intelligence measures than those who take English. Again, the non sequitur is staggering. The analogous argument is that practicing the piano is useless, because people who practice the violin get into colleges at least as good as those who practice the piano.
Claim 3: "the effects of environmental intervention erode over time"
Supporting link: http://econlog.econlib.org/archives/2010/11/fade-out_teache....
The link shows that good teachers can make students a lot better on immediate test results than on longer-term measures of subject mastery. While this is interesting, it has zero relevance to the main argument, which was that grueling hours of practice have no effect on students' character.
Overall, the question posed and the approach are very interesting, but the subsequent argumentation turns out to be shaky and implausible. What a disappointment!