I'dgo for the more subdued colours as well. Your kids or someone elses chewing your jumper 
I was thinking of changing the colour to blue, since yep this is my little "boy" (the little girl is also mine!). I changed my mind for a couple of reasons, a) everything "boy" related is blue, b) blue could be a little cold. I'm really not sure about green (although I know there are other colours)
Note the main reasons for having a newly found interest in "Child Portrait Photos" is that I have very little time in front of the camera, and when I do I usually have two very small children in close proximity. Hence, why not just combine the two activities and use them as subjects!
I also would like to get a couple of canvas photos of the kids when their small and more importantly, so would the wife!
I'm actually surprised that it’s not as hard as I though it would be. Once you have the lighting setup ok, just shoot away and the law of averages ensures you get a few good shots. I think your right; this would be easy money (although a little boring)