Brother/Sister - Completely Different Children

I know each child is different...  but I really thought having a brother and sister (raised by the same parents and same discipline), they would be similar???  I was wrong.

Kayson and Cora are so opposite.

Sleeping:

• Kayson falls asleep at the drop of a hat... literally within minutes of going to bed, that kid is sleeping hard.  Cora takes much longer (about 20 to 30 minutes to fall asleep).  She lays in there talking and singing all while rubbing her eyes.  I mean - GO.TO.SLEEP!! 
• Kayson wants/needs/and stays covered up all night long when sleeping (sometimes his head is covered up when I wake him in the morning!). Cora starts uncovered, then in the morning she has her big soft blanket over her neck and body, but her legs are always out.

Eating:

• This is an age one, I think --- Kayson has gotten a ton better about eating what I make.  He's been eating really well lately (liking meats more), without much complaints.  Cora, on the other hand, fusses at every meal, really only wanting mac & cheese (which she only will eat half the time!!!).  She just doesn't eat well for us... 
• Kayson eats the frosting off of cakes/cupcakes (like his Dad).  Cora scrapes it off (like me).  

Playing:

• Cora can play by herself - toys, baby dolls, using her imagination.  Kayson has never been one to play alone - besides electronics.