I was a mini insomniac as a baby/child.
Brother and sister slept great.
Brother was a mega picky eater. Sister and I weren't.
Brother had a more difficult temperament, that blossomed into vile when he hit his mid 30s. I am Ok-ish. Sister was, and is angelic.
Brother and I have brown hair (as does my DH). My sister is blonde.
I got an blonde, angelic, non sleeper (until he was six years old and the enforced naps at kindergarten ceased) with the occasional bout of fussy eating.
If it is my parenting failure that he was a mini insomniac then I want credit for the angleic temperament. We can all ignore that he is basically a male photocopy of my sister and sit around congratulating me on my parenting instead. 
I think what you do as a parent matters. Certainly in terms of loving, nurturing and providing boundries/stability etc. All aimed at giving your kid the best chance to make the most of the great attributes they have, and being in a good position to avoid their less helpful attributes causing them problems.
But the raw material that pops out after nine months and peers at you bleerily.... I dunno, thinking about my son over the years and looking at his 14yo self in the now, I think that's is likely down to a genetic lottery.
Nothing would make that child sleep. Six fecking Y E A R S of waking me up in the wee hours. And now he is all hormonally challenged he has taken to sleep walking, coming into our room, giving me his pillow, sleep-yakking about basketball and then wandering off back to bed. So we are back to waking me up in the wee hours again. On the bright side, I spent years waking up as a kid/teen wondering which fucker had nicked my pillow again and never did get to the bottom of it. I think DS has, somewhat belatedly, provided the solution to that mystery.