Differences in My Daughters

My daughters are very similar in appearance, but they have some serious differences as well:

• Elizabeth is always warm and thrives in the cold; she was born in the summer and almost never wore a onesie or socks. I never needed baby blankets with her and didn't really see the use for them. Amelie is very cold-blooded just like me and always needs a onesie and socks. I love to cuddle her under the very necessary baby blankets!
• Elizabeth only took a bottle once and rarely rode in a baby carrier - I simply never tried to use them with her. Amelie has taken 3 bottles already and I depend on the baby carrier frequently!
• Elizabeth at two months old was already showing stranger anxiety and wouldn't go in the church nursery without screaming. I was frequently paged to come get her because she was inconsolable. Amelie spent an entire 40 minutes in the church nursery today and was sleeping in someone's arms when I returned to pick her up. So far, she's pretty willing to go to strangers.
• Elizabeth was waking up about twice a night at this point and didn't sleep through the night until she was 9 months old. Amelie wakes up once each night to eat and has actually slept through the night about 5 times now (just not consecutively).

I'm curious to know how much these differences is due to personality and how much is due to a less uptight parenting style. I suppose I'll never find out.