Yes, you would capitalize it because it's an important noun.
Personally, no. I believe many people can make a small impact on your life at any given moment. But in some cases, it you can meet people then later have no significant connection/bond with them so they were more of a ‘come and go’ type that didn’t benefit you or your life.
Because she could not contain her own curiosity. Just like how Eve ate the forbidden fruit In the Graden of Eden, and like they say "curiosity killed the cat"