Family Portrait

This is an oil painting I did of my sister's family. In general I'm pretty happy with it because I've never done a painting of this complexity. I think the likenesses are pretty good, which was my biggest concern. However, as my teacher pointed out, the main issues are with the colors. Everything feels a bit too plastic and cut-out, and the flesh tones are too gray. Also the yellow bench, the blue jeans, and the red wall are actually the three primary colors (or 'Triad' scheme, thank you Adam), which looks kind of strange. I'm going to be modifying this, but I just wanted to post it the way I submitted it.