Things that could affect your baby

Ok so my little sister had her son abt a year ago & he's the smartest & sweetest baby ever. He's also EXTREMELY active, doesn't sleep well throughout the night, is still on the bottle, & doesn't really like to be touched or cuddled with. I get that every baby is different but when NUMEROUS ppl have told me that he's different than how their sons were or how my own brother was, that worries me. I think he needs some direction & guidance & my sister wasn't the nicest to him when he was just a baby (he's one now) so he's kinda got this slight temper which we've warned her about. Then my aunt explained how her son was a calm laid back baby, didn't get into everything in site & she'd play classical music for him. Now he's in high track classes & super smart. 
My question is, what have do you think affects your child's development in the womb and after in terms of their attitude & how active or non active they'll be? I know boys are usually more active anyways but I really hope my son is active when he needs to be & doesnt give me a hard time lol. I just feel like my nephew didn't get to be active enough as a baby baby bc my sister would keep him bottled up in his car seat (which he now hates bc he sat in it too much) restricting his movement to explore more.