Don't be too illusioned about controls "locking up," a low time pilot can be taught to stay out of Vne and maintain control of his aircraft, this is not that hard and can easily be demonstrated during initial training.
This is pure conjecture but would an inexperienced,relatively untrained,kamikaze pilot ever have flown in a situation in which the "normal" controls became ineffective?
If the first time he ever found that he could not manoeuvre using,for example,his ailerons was his last dive onto a US warship I very much doubt that he would be able to make adjustments in other ways. This would explain the warning in the "Kamikaze manual" about diving too fast.
Cheers
Steve