Oh wow! I love this concept. Love what you did with the background and I like their costumes/garb/clothing. Nicely done and their atmosphere shows that they are good friends. It's got that warm fuzzy feeling to it.
Oh yeah! Out of the 6 sets of siblings on my dad's side of the family (8 children, all married, only 7 of the couples had children, 6 couples had 2 kids.) My sister and I are the only ones that you can noticeably see that we get along really well.
Wow I in my family we have half that amount because my mother could only have 4 kids. Ha ha same with the youngest and I (the eldest). We're the only ones that really do get along well.