Woodie Guthrie and Virginia Woolf are two more. They were both superb artists and overachievers, but dysfunctional individuals. In Woolf's case, this was at least in part due to a series of horrendous events in her family, including her sexual abuse by a step-brother.

Abe Lincoln's mother died when he was young as well. Great politician. Suspected of suffering from depression for most of his life, yet by all measures that I know he is a successful figure who achieved much.

You might want to expand your thesis to include the idea that, although the early death of a parent casts a pall over the life of the child, those with a firm support system and a healthy sense of self can use their sadness to their advantage.

Early death of the mother was a lot more prevalent in the bad old days of childbed fever and mysterious "women's ailments" that were not studied extensively by doctors.